The potential of a standard hydrogen (S.H.E.) electrode under the given conditions is -0.126V.
A standard hydrogen electrode (SHE) is a reference electrode used to estimate the standard electrode potentials (E°) of half-reactions. It is made up of a platinum electrode coated in platinum black (Pt) and a hydrogen (H2) electrode dipping into an acidic solution of HCl. The pressure of H2 is measured at 1.0 atm, and the concentration of H+ is maintained at 1.0 mol/L. The potential of the SHE is set to 0.000 V at all temperatures, and other electrode potentials are compared to it to determine their standard reduction potentials.
Using the Nernst equation, we can compute the potential of the SHE : E = E° - (RT/nF)lnQ, where E is the cell potential, E° is the standard cell potential, R is the gas constant, T is the temperature, n is the number of moles of electrons transferred in the redox reaction, F is the Faraday constant, and Q is the reaction quotient.
The given conditions[H+] = 0.77 MPH2 = 1.4 atm T = 298 K
We can use the Nernst equation to calculate the potential of the SHE under these conditions as follows:
E = E° - (RT/nF)lnQ,
where E° = 0.000 VR = 8.314 J/(mol*K)n = 2 F = 96,485 J/V*KpH2 = 1.4 atm
Q = [H+]2/[H2]E = E° - (RT/nF)lnQ= 0.000 - (8.314*298/2*96,485)*ln (0.77/1.4^2)= 0.000 - 0.000688= -0.126 V
Therefore, the potential of the standard hydrogen electrode (SHE) under the given conditions would be -0.126 V.
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water, h2o, and hexane, c6h14, are commonly used as laboratory solvents because they have different physical properties and are able to dissolve different types of solutes. 32. explain, in terms of the molecular polarity, why hexane is nearly insoluble in water
Hexane, C6H14, is a non-polar molecule, meaning that its electric charge is evenly distributed. On the other hand, water (H2O) is a polar molecule, with an uneven distribution of electric charge. Since the two molecules have opposite polarities, they do not interact with one another, leading to the nearly insoluble nature of hexane in water.
When explaining, in terms of the molecular polarity, why hexane is nearly insoluble in water, it's crucial to consider the nature of the molecules, their polarity, and their ability to interact with one another.
What is hexane?Hexane, with the chemical formula C6H14, is a saturated hydrocarbon with a boiling point of 69°C. It's an odorless liquid that's colorless, and it's frequently utilized as a solvent in the laboratory. When hexane molecules are considered, they are all nonpolar molecules, meaning that the electrons are distributed uniformly among the atoms, and there is no permanent charge on any part of the molecule.
What is water?Water (H2O) is a polar molecule with a partial positive charge on its hydrogen atoms and a partial negative charge on its oxygen atoms. It's a very common solvent in laboratories because it's extremely polar and can dissolve a wide range of substances. It's because of the difference in the polarity of water and hexane molecules that hexane is nearly insoluble in water.
The reason hexane is insoluble in water is that water is an incredibly polar substance, while hexane is a nonpolar substance. The polar water molecules are attracted to other polar substances and repelled by nonpolar substances like hexane, which has no charge to attract polar water molecules.
Therefore, as a result, hexane does not dissolve in water and is nearly insoluble.
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what is the formula for chlorine
Which concept accounts for the whole-number subscripts in chemical formulas?A. law of multiple proportionsB. Avogadro's lawC. conservation of energyD. conservation of matte
Answer:
A)law of multiple proportions
Explanation:
determine the limiting reactant, amounts of each product formed, and the amount by which the excess reactant is for a reaction between 12.0 grams of nh3 and 15.0 grams of o2.
To determine the limiting reactant, amounts of each product formed, and the amount by which the excess reactant is for a reaction between 12.0 grams of NH₃ and 15.0 grams of O₂, the balanced chemical equation and stoichiometry must be used.
The balanced chemical equation for the reaction between NH₃ and O₂ is:
4NH₃ + 5O₂ → 4NO + 6H₂O
To determine the limiting reactant, the amounts of reactants must be converted to moles. The molar mass of NH3 is 17.03 g/mol and the molar mass of O₂ is 32.00 g/mol.
12.0 g NH₃ × (1 mol NH3/17.03 g NH₃) = 0.705 mol NH
315.0 g O₂ × (1 mol O2/32.00 g O₂) = 0.469 mol O₂
The stoichiometry of the balanced chemical equation indicates that 4 moles of NH₃ reacts with 5 moles of O₂. The mole ratio of NH₃ to O₂ is 4/5 or 0.8. Since the mole ratio of NH₃ to O₂ is greater than the actual mole ratio of 0.705/0.469 or 1.50, NH₃ is the excess reactant and O₂ is the limiting reactant.
To determine the amount of each product formed, the mole ratio of products to limiting reactant must be used. The mole ratio of NO to O₂ is 4/5 or 0.8, and the mole ratio of H₂O to O₂ is 6/5 or 1.2. Since O₂ is the limiting reactant, the amount of NO and H₂O that can be produced is based on the mole ratio to O₂.
0.469 mol O₂ × (4 mol NO/5 mol O₂) × (30.01 g NO/1 mol NO) = 0.601 g NO
0.469 mol O₂ × (6 mol H₂O/5 mol O₂) × (18.02 g H₂O/1 mol H₂O) = 0.674 g H₂O
The amount of excess NH₃ is determined by subtracting the moles of NH₃ used from the moles of NH₃ added.
0.705 mol NH₃ − (0.469 mol O₂ × 4 mol NH₃ / 5 mol O₂) = 0.408 mol NH₃
Thus, the limiting reactant is O₂, 0.601 g NO and 0.674 g H₂O are produced, and there is 0.408 mol of excess NH₃.
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What volume of air is present in human lungs if 0.19 mol are present at 312K and 1.3 atm?
A. 0.066
B. 2.9L
C. 5.5L
D.3.7L
Answer:
The answer is D - 3.7 L.
Indicate which substance in each of the following pairs of substances you expect to have higher entropy. assume that you have a mole of each substance and all substances are at the same temperature? a. H2S2(g) b. H2S2(l) [Choose] a. CsBr(s) b. Sro(s) [Choose] a. H2O(l) b. H2O2(l) [Choose ] a. SO3(g) b. SO3(s) [Choose]
H₂S₂(g) is expected to have higher entropy than H₂S₂(l). CsBr(s) is expected to have higher entropy than Sro(s). H₂O(l) is expected to have higher entropy than H₂O₂(l). SO₃(g) is expected to have higher entropy than SO₃(s).
The entropy of the substance is determined by the amount of randomness and disorder it has. The higher the entropy, the greater the randomness of the substance. At the same temperature and pressure, a pure solid has a lower entropy than a pure liquid, which in turn has a lower entropy than a pure gas. The entropy of a substance is determined by its physical state, molecular structure, and the quantity of the substance.
H₂S₂ is a chemical compound with two sulfur atoms and two hydrogen atoms. The state of H₂S₂(g) is a gas, and H₂S₂(l) is a liquid. Since the gas state is more disordered than the liquid state, H₂S₂(g) is expected to have higher entropy than H₂S₂(l).
Both CsBr(s) and Sro(s) are in the solid-state. However, CsBr(s) has a higher entropy than Sro(s) because it has more molecules. This means that CsBr(s) has a greater degree of randomness and disorder than Sro(s).
H₂O(l) and H₂O₂(l) are both liquid states, but H₂O(l) has higher entropy because it has more degrees of freedom. H₂O(l) can rotate and translate freely, while H₂O₂(l) has a rigid structure that does not allow for the same degree of movement.
SO₃(g) is in the gaseous state, while SO₃(s) is in the solid-state. At the same temperature, the entropy of SO₃(g) is greater than that of SO₃(s) because the gas state is more disordered than the solid-state.
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Chromium crystallizes with a body-centered cubic unit cell. The radius of a chromium atom is 125 pm. Calculate the density of solid crystalline chromium in g/cm^3.
The density of solid crystalline chromium in g/cm³ is 7.19 g/cm³.
A unit cell is the smallest group of atoms, molecules, or ions in a crystal that can repeat indefinitely to form the whole crystal. A unit cell is used to describe the basic repeating arrangement of atoms, ions, or molecules in a crystal. The density of a material is its mass per unit volume, and it is measured in grams per cubic centimeter (g/cm³) or kilograms per cubic meter (kg/m³).
The density of a unit cell formula:ρ = (Z × M) / (a³ × N)ρ = Density of unit cell Z = Number of atoms per unit cell M = Atomic weight of atoms in a unit cella = Edge length of the cube N = Avogadro's numberThe unit cell volume (Vc) = a³Z = 2 (as chromium has a BCC crystal structure, the number of atoms per unit cell is 2)M = 52N = 6.022 × 10²³ρ = (2 × 52) / (4 × 125³ × 6.022 × 10²³)ρ = 7.19 g/cm³
Therefore, the density of solid crystalline chromium in g/cm³ is 7.19 g/cm³.
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Nitrogen oxides are pollutants, and common byproducts of power plants and automobiles. NO2 can react with the NO in smog, forming a bond between the N atoms. Draw the structure of the resulting compound, including formal charges. Use this table to predict the energy of the bond in NO. about 200 kJ/mol about 400 kJ/mol about 600 kJ/mol Use the same table to predict the energies of the bonds in NO2. both are about 200 kJ/mol both are about 400 kJ/mol both are about 600 kJ/mol one is about 200 kJ/mol and the other is about 600 kJ/mol *indicates an energy that is an average for that type of bond in several different molecules.
The structure of the resulting compound from the reaction of NO and NO2 is the compound is known as dinitrogen pentoxide, N2O5.The bond energy in NO is about 631 kJ/mol.The bond energies in NO2 are both about 240 kJ/mol.
N2O5 is the chemical formula for dinitrogen pentoxide, often known as nitrogen pentoxide or nitric anhydride. It belongs to the family of chemicals known as binary nitrogen oxides, which simply consists of nitrogen and oxygen. It exists as colourless crystals that sublimate at a temperature just above ambient to produce a colourless gas. Dinitrogen pentoxide, an unstable and potentially harmful oxidant, was originally employed as a reagent for nitrations when dissolved in chloroform, but nitronium tetrafluoroborate has completely replaced it (NO2BF4).
N2O5 is a rare instance of a substance that can change its structure based on the environment. The solid is a salt, nitronium nitrate, consisting of distinct nitronium cations [NO2]+ and nitrate anions [NO3]−; although in the gas phase and under some other situations it is a covalently-bound molecule.
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A sample of iron wire reacts with oxygen to form iron(III) oxide. If 3.58g of the wire yields 5.00g of the iron(III) oxide, calculate the percentage purity of the iron.
How do I do this question? Thanks!
Answer:
We can start by finding the amount of iron used in the reaction:
Iron (Fe) is the limiting reagent since it is completely used up in the reaction.
Molar mass of Fe = 55.845 g/mol
Moles of Fe = mass / molar mass = 3.58 g / 55.845 g/mol = 0.064 moles
The balanced chemical equation for the reaction is:
4Fe + 3O2 → 2Fe2O3
From the equation, we can see that 4 moles of Fe react with 3 moles of O2 to produce 2 moles of Fe2O3.
Moles of Fe2O3 produced = mass / molar mass = 5.00 g / (2 x 159.69 g/mol) = 0.01567 moles
Since 4 moles of Fe reacts with 2 moles of Fe2O3, the theoretical yield of Fe2O3 from 0.064 moles of Fe is:
Theoretical yield of Fe2O3 = (0.064 mol Fe) x (2 mol Fe2O3 / 4 mol Fe) x (2 x 159.69 g/mol Fe2O3) = 12.746 g
The percentage purity of iron is:
Percentage purity = (actual yield / theoretical yield) x 100%
Percentage purity = (5.00 g / 12.746 g) x 100% = 39.26% (rounded to two decimal places)
Therefore, the iron wire is 39.26% pure.
Which of the following complexes will absorb a photon with the lowest energy?
Group of answer choices
A. [Co(OH)6]3-
B. [Co(SCN)6]3-
C. [Co(NO2)6]3-
The complex that will absorb a photon with the lowest energy is [Co(OH)6]3-. The correct answer is option A
Co(OH)6]3- is the complex that absorbs a photon with the lowest energy. It is because of the crystal field effect. The complex [Co(OH)6]3- has the lowest energy for the d-electrons of the cobalt ion. A photon is an elementary particle that forms a light beam. It has a small mass and no charge. A photon has wave-particle duality, which means it exhibits properties of both a wave and a particle. Photons are electromagnetic radiation particles, which means they have both electric and magnetic components.
The lowest energy is defined as the minimum energy that a system can have. It is the energy state that is energetically stable. Photons have energy, and the energy of the photon is directly proportional to its frequency. The energy of a photon can be used to determine the energy of the electron that absorbs it.
A weak field ligand environment means that there is a small energy gap between the t2g and eg orbitals. As a result, it absorbs photons with the lowest energy, according to the spectrochemical series. In comparison to the other complexes, [Co(OH)6]3- has a low-energy gap, which makes it the most stable.
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Carbon dioxide gas is collected in a laboratory experiment to determine the molar mass of the compound. At 294 Kand 1.01 atm, 1.008 grams of co2 was collected when a 500 mL flask was filled with the evolved co2. What is the experimental molar mass of co2? a. 41.5 g/molb., 44.0 g/mol c. 46.9 g/mol d 48.2 g/mol
The experimental molar mass of CO2 collected in a laboratory experiment is 44.0 g/mol.
When carrying out laboratory experiments, carbon dioxide gas is collected to determine the molar mass of the compound. When a 500 mL flask was filled with the evolved CO2 at 294 K and 1.01 atm, 1.008 grams of CO2 was collected. It is required to determine the experimental molar mass of CO2. To solve the problem, we will make use of the ideal gas law formula:
P.V = n.R.T Where,P = 1.01 atmV = 500 mL = 0.500 Ln = number of moles of CO2R = 0.0821 L.atm.K-1.mol-1T = 294 K Substituting the values in the formula, we get;1.01 atm × 0.500 L = n × 0.0821 L.atm.K-1.mol-1 × 294 K1.01 × 0.500 = n × 24.79n = (1.01 × 0.500) / 24.79n = 0.02039 moles of CO2. We know that the mass of CO2 that was collected is 1.008 grams.Therefore, the molar mass of CO2 = mass / number of moles = 1.008 g / 0.02039 mol = 49.38 g/mol
But, we know that CO2 has a molar mass of 44.01 g/mol. Hence, the value of 49.38 g/mol is not the experimental molar mass of CO2 and so, we have to calculate the experimental molar mass of CO2 as follows:Experimental molar mass of CO2 = mass / number of moles = 1.008 g / 0.02039 mol = 49.38 g/mol. Actual molar mass of CO2 = 44.01 g/mol.
Experimental error = | experimental value - actual value | / actual value × 100%.Substituting the values in the formula, we get;
Experimental error = | 49.38 - 44.01 | / 44.01 × 100%
Experimental error = 12.2% ≈ 12%.
Therefore, the experimental molar mass of CO2 is 44.0 g/mol (Option b).
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Write a chemical equation for HNO3(aq) showing how it is an acid or a base according to the Arrhenius definition.Express your answer as a chemical equation. Identify all of the phases in your answer.Part CWrite a chemical equation for HF(aq) showing how it is an acid or a base according to the Arrhenius definition.Express your answer as a chemical equation. Identify all of the phases in your answe
Part A The chemical equation for HNO3 showing it is acid is:-
HNO3 (aq) → H+ (aq) + NO3- (aq)
The phases are HNO3 (aq) = aqueous solution, H+ (aq) = aqueous solution and NO3- (aq) = aqueous solution.
Part B The chemical equation for HF showing it is acid is:-
HF (aq) → H+ (aq) + F- (aq)
The phases are HF (aq) = aqueous solution, H+ (aq) = aqueous solution, and F- (aq) = aqueous solution.
HNO3 (aq) is an acid according to the Arrhenius definition because the chemical substance HNO3 (nitric acid) dissociates in an aqueous solution to release hydrogen ions (H+).
HF (aq) is an acid according to the Arrhenius definition because the chemical substance HF (hydrofluoric acid) dissociates in an aqueous solution to release hydrogen ions (H+).
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For the weak acid, identify the expression for the acid ionization constant Ka. Ο Κa= (H2O|HSO2)/(H,SO3] O Ka = [H3O+](HSO3) /H2SO3) O Ka = [H30*](HSO3")[S03?-) /(H2SO3) O KA= [H3O+] [HSO"][S02?") /(H2SO3]
For the weak acid, the expression for the acid ionization constant Ka is given by the equation O Ka = [H3O+](HSO3) /H2SO3.
How to find acid ionization constant Ka?
The acid ionization constant Ka of a weak acid HA is given by the equation shown below, where [H3O+] represents the hydrogen ion concentration of the solution, and [A-] represents the conjugate base of the acid. Ka = [H3O+][A-]/[HA]
It is possible to calculate the acid dissociation constant of a weak acid by measuring the degree of ionization of the acid. A higher degree of ionization indicates a stronger acid, while a lower degree of ionization indicates a weaker acid.
The acid ionization constant Ka is used to compare the strengths of various acids.
The correct option is O Ka = [H3O+](HSO3) /H2SO3). The acid ionization constant Ka for a weak acid is the equilibrium constant for the ionization reaction of the acid. The acid ionization constant for a weak acid, Ka, is expressed as:
Ka = [H3O+][A-]/[HA]
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Consider that Fe3+ is a d5 metal center. If it is surrounded by weak-field ligands in an octahedral configuration, how many electrons are in the lower three and upper two metal orbitals, respectively.
A. 3,2
B. 2,3
C. 5,0
D. 1,4
The correct answer is 3, 2. If Fe3+ is surrounded by weak-field ligands in an octahedral configuration, there will be 3 electrons in the lower three metal orbitals and 2 electrons in the upper two metal orbitals. So, the correct option is A.
An octahedral complex is a complex where the coordination sphere of a central metal ion is composed of six ligands that are located at the corners of an imaginary octahedron. The octahedral arrangement of six ligands is the most common coordination mode. The configuration of the eight corners of an octahedron is made up of six ligands, with the metal center located at the center.
The d5 electron configuration for Fe3+ is t2g3eg2, which is filled according to Hund’s rule with the lower-energy orbitals being filled first. According to the weak-field ligand hypothesis, the t2g orbitals will be relatively unaffected in energy, whereas the eg orbitals will be significantly raised in energy.
As a result, the three electrons in the t2g orbitals will occupy the lower-energy orbitals, while the two electrons in the eg orbitals will occupy the higher-energy orbitals. As a result, there will be 3 electrons in the lower three metal orbitals and 2 electrons in the upper two metal orbitals. The correct option is A. 3, 2.
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(a) What would you expect the pH of pure water to be?(b) What colour would the universal indicator show in an aqueous solution of sugar? Why?(c) A sample of rain water turned universal indicator paper yellow. What would you expect its pH to be? Is it a strong or a weak acid?
(a) The pH of pure water is 7, which is neutral. (b) The universal indicator would show a yellow color in an aqueous solution of sugar, because sugar is a neutral compound with a pH of 7.(c) The pH of the rain water is likely around 5 or 6, which indicates a weak acid.
pH is less than 7 since yellow color indicates acidic rainwater. Rainwater has an acidic pH because it dissolves atmospheric carbon dioxide (CO2), sulfur dioxide (SO2), and nitrogen oxides (NOx), forming weak carbonic, sulfuric, and nitric acids.
Rainwater that has a pH below 5.6 is considered to be acid rain. Therefore, the acid present in rainwater is a weak acid because the pH of the rainwater is above 1.
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In the illustration, which solute will dissolve first? A) solute in tank B will dissolve first B) solute in tanks A and B will dissolve at equal rates C) solute in tank A will dissolve first
A) The solute in tank B will dissolve first, is the key response.Temperature, pressure, and concentration are only a few examples of the variables that affect a solute's solubility in a solvent. As the water in both tanks A and B is originally pure.
in this instance the solute in tank B will dissolve first due to its larger concentration than in tank A. The concentration gradient between the solute and the water narrows as the solute in tank B dissolves and diffuses into the surrounding water, slowing the rate of dissolution. The solute in tank A will also eventually dissolve, but because of its lower initial concentration, it will do so more gradually.I am unable to tell which solute will dissolve first because the relevant illustration is not given. However, a number of variables, including temperature, pressure, and the chemical makeup of the solute and solvent, affect how soluble a solute is in a solvent. The solute that is more soluble in the given solvent will often dissolve first. It is impossible to predict which solute will dissolve first without more details or context.
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What is the tendency of electrons to enter orbitals of lowest energy first? A. atomic orbital B. Aufbau principle C. electron configuration D. ground state E. Pauli exclusion principle F. Heisenberg uncertainty principle
The tendency of electrons to enter orbitals of lowest energy first is known as the Aufbau principle. In chemistry, the Aufbau principle is used to predict the ground state of an atom and to understand the electronic structure of elements.
Aufbau principle is the method of building an atom's electronic structure by adding electrons one at a time to the lowest energy orbitals available until all of the electrons have been added.
The lowest-energy orbitals, such as 1s, are filled with electrons first because electrons have the most negative charge and are thus drawn to the positively charged atomic nucleus. Electrons in orbitals of equal energy (such as the three 2p orbitals) must occupy each of them singly before they begin pairing up to form electrons pairs (spin pairing). To avoid filling two orbitals of the same energy with electrons, electrons must fill singly first.
The Aufbau principle governs the order in which orbitals are filled and explains why the electron configuration of each atom is unique.
In a nutshell, the tendency of electrons to enter orbitals of lowest energy first is known as the Aufbau principle.
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When it fails to occur, is the chemical basis for a metabolic syndrome in which the body fails to breakdown fatty acids?
Yes, the chemical basis for a metabolic syndrome is the failure of the body to breakdown fatty acids.
What is Metabolic syndrome?Metabolic syndrome is used to describe a collection of health problems that increase the risk of developing other diseases such as diabetes, heart disease, and stroke. The primary cause of metabolic syndrome is obesity, which is why it is frequently referred to as "obesity syndrome."
The syndrome is also linked to other genetic and environmental factors that contribute to insulin resistance, inflammation, and high blood pressure, as well as a failure to break down fatty acids properly in the body. Thus, the chemical basis for metabolic syndrome is the failure to break down the fatty acids in body. This chemical problem can contribute to the development of other fatal diseases and health problems.
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Buffer solutions containing Na2CO3 and NaHCO3range in pH from 10.0 to 11.0. The chemical equation below represents the equilibrium between CO32- and H2O, and the table lists the composition of four different buffer solutions at 25°C.CO32- (aq) + H2O (l) ⇄ HCO3- (aq) + OH- (aq);Kb= 2.1 × 10-4 at 25°CBuffer [NaHCO3] Na2CO3 pH1 0.150 0.100 ?2 0.200 0.200 10.323 0.100 0.100 10.324 0.100 0.200 ?Which of the following chemical equilibrium equations best shows what happens in the buffer solutions to minimize the change in pH when a small amount of a strong base is added?A. H3O+(aq) + OH−(aq) ⇄ 2 H2O(l)B. HCO3−(aq)+ OH−(aq) ⇄ CO32−(aq) + H2O(l)C. CO32−(aq) + H3O+(aq) ⇄ HCO3−(aq) +H2O(l)D. CO32−(aq) + H2O(l) ⇄ HCO3−(aq)+ OH−(aq)
The correct answer is D. [tex]CO_3^{2-}(aq) + H_ 2O(l) \rightleftharpoons HCO_3^-(aq) + OH^-(aq)[/tex]. This chemical equilibrium equation best shows what happens in the buffer solutions to minimize the change in pH when a small amount of a strong base is added.
Buffer solutions containing [tex]Na_2CO_3[/tex] and [tex]NaHCO_3[/tex] range in pH from 10.0 to 11.0. The chemical equation given represents the equilibrium between [tex]CO_3^{2-}[/tex] and [tex]H_2O[/tex], and the table lists the composition of four different buffer solutions at 25°C. When a small amount of a strong base is added to a buffer solution, the pH will start to increase. This equation helps to minimize the change in pH by shifting the equilibrium so that the concentration of [tex]HCO_3^-[/tex] is increased. This decreases the concentration of [tex]OH^-[/tex] and the pH increases less than it would if the equilibrium had not shifted.
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Complete the following radioactive decay problem.
234 U → 4^He +
92. 2
The complete radioactive decay equation is as follows:
234/92 → 4/2He + 230/90 Th
What is a radioactive decay?Radioactive decay is a several processes by which unstable nuclei emit subatomic particles and/or ionizing radiation and disintegrate into one or more smaller nuclei.
According to this question, uranium with the mass number 234 and atomic number 92 undergoes a radioactive decay as follows:
234/92 U → 4/2 He + 230/90 Th
Uranium-234 nuclei decay by alpha emission to thorium-230, except for the tiny fraction (parts per billion) of nuclei that undergo spontaneous fission.
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Calculate the pH at 25°C of a 0.49M solution of ethylammonium bromide C2H5NH3Br . Note that ethylamine C2H5NH2 is a weak base with a pKb of 3.19 . Round your answer to 1 decimal place.
how many chirality centers are there in an aldohexose?a. 3b. 4c. 5d. 6
There are 4 chirality centers in an aldohexose. The correct answer is option b.
Aldohexoses are six-carbon monosaccharides with a carbonyl functional group (aldehyde group) and five other carbon atoms, each of which is associated with an alcohol functional group in their straight-chain form. The carbonyl carbon, which is referred to as the anomeric carbon, determines the stereochemistry and the cyclic form of aldohexoses.
Chirality centers are carbon atoms that have four distinct substituents bonded to them, resulting in the ability to exist as stereoisomers. These stereoisomers are mirror images of each other and cannot be superimposed upon each other.Therefore, it is important to count the number of chirality centers present in the aldohexose structure.
There are four chirality centers in aldohexose, which are present at carbon atoms 2, 3, 4, and 5.
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Multiple choice: A solution is prepared by dissolving 1.0 g of NaOH in a total volume of 250 mL solution. Then 10.0 mL of this solution is withdrawn and added to 90.0 mL of water. What is the pH of the final solution?a. 11.50b. 12.00c. 12.50d. 11.00e. 13.50
A solution is prepared by dissolving 1.0 g of NaOH in a total of 250 mL of solution. Then 10.0 mL of this solution is withdrawn and added to 90.0 mL of water. The pH of the final solution is 11. Here option D is the correct answer.
To determine the pH of the final solution, we need to calculate the concentration of hydroxide ions (OH-) first.
1.0 g of NaOH is dissolved in a total volume of 250 mL of solution, which is equivalent to 0.004 moles of NaOH (since the molar mass of NaOH is 40.0 g/mol). Therefore, the concentration of NaOH in the original solution is:
c(NaOH) = 0.004 moles / 0.250 L
= 0.016 M
When 10.0 mL of this solution is added to 90.0 mL of water, the resulting concentration of NaOH is diluted by a factor of 10. Therefore, the concentration of NaOH in the final solution is:
c(NaOH) = 0.016 M / 10
= 0.0016 M
Since NaOH is a strong base, it completely dissociates in water to form one mole of hydroxide ions (OH-) for every mole of NaOH. Therefore, the concentration of hydroxide ions in the final solution is also 0.0016 M.
To calculate the pH of the solution, we use the following equation:
pH = 14 - pOH
Since the concentration of hydroxide ions is 0.0016 M, the pOH is:
pOH = -log[OH-]
= -log(0.0016)
= 2.80
Therefore, the pH of the solution is:
pH = 14 - pOH
= 14 - 2.80
= 11.20
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To qualitatively aid in differentiating malabsorption and maldigestion, 2 slides are made from the stool specimen, pretreated with ethanol (slide 1) or acetic acid (slide 2) and stained with?eosin-nigrosinoil red Osafraninmethylene blue
The two slides prepared from a stool specimen for the purpose of differentiating malabsorption and maldigestion are prepared using ethanol (slide 1) or acetic acid (slide 2) and then stained with Eosin-Nigrosin. Oil Red O, and Methylene Blue. Eosin-Nigrosin is used to detect fats, Oil Red O detects neutral fats, and Methylene Blue detects starch. If there is an abnormally high presence of fat and starch, it is indicative of malabsorption. If the presence of fat is normal but the presence of starch is abnormally high, it suggests maldigestion.
Ethanol is used in slide 1 as it preserves the shape of the neutral fats for observation. Acetic acid is used in slide 2 to dissolve the neutral fats, thereby allowing for the visualization of starch granules which would otherwise be hidden by the fat droplets.
Eosin-Nigrosin, Oil Red O, and Methylene Blue work in tandem to provide a visual understanding of the digestive processes that have taken place, enabling the physician to diagnose the patient. This diagnostic method is relatively simple and non-invasive, making it a viable choice for most patients.
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which scientist conducted the gold foil experiment and discovered that the atom has a positively charged nucleus in the center, and that most of that atom is empty space?rutherfordgoldsteinalessandro volta
Ernest Rutherford is the physicist who carried out the gold foil experiment and found that the atom has a positively charged nucleus in the centre and that the majority of that atom is empty space.
The gold foil experiment was carried out in 1911 by Ernest Rutherford, who attacked a thin sheet of gold foil with alpha particles and tracked their scattering patterns.
Based on his discoveries, he put forth the nuclear model of the atom, which argues that the majority of the atom is made up of empty space and contains a positively charged nucleus at its core. The advancement of the contemporary atomic theory was greatly aided by this experiment.
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The question is if the atmospheric pressure is 0. 993 atm and the height of the water column at the end of the experiment is 16. 5cm, what is the total pressure of the gas in the eudiometer? and if the total pressure is at 20,5 degree centimeter is 580 mmhg. What is the partial pressure of the h2 gas
We must apply Dalton's Law of Partial Pressures, which states that the total pressure of a gas mixture is equal to the sum of the partial pressures of each gas in the mixture, to determine the partial pressure of H2 gas in the eudiometer.
The atmospheric pressure of 0.993 atm must first be converted to mmHg using the formula: 0.993 atm x 760 mmHg/atm = 755.88 mmHg.
The total pressure of the gas inside the eudiometer may then be determined by:
Total pressure equals the sum of atmospheric pressure and water column pressure.
Total pressure = 16.5 cm x 1 mmHg/cm plus 755.88 mmHg
Pressure overall is 771.38 mmHg.
Eventually, we can determine the partial pressure of H2 gas using Dalton's Law and the supplied total pressure of 580 mmHg:
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How do I calculate the moles of calcium chloride with a mass of 1. 11 g
You need to know the molar mass of calcium chloride in order to calculate the moles of calcium chloride with a mass of 1.11 g. The total atomic masses of all the atoms in a single compound molecule make up the molar mass.
According to its chemical formula, calcium chloride is composed of two chlorine atoms (atomic mass = 35.45 g/mol) and one calcium atom (atomic mass = 40.08 g/mol). As a result, calcium chloride has the following molar mass:
CaCl2 has a molar mass of 110.98 g/mol (40.08 g/mol + 2 x 35.45 g/mol).
The number of moles of calcium chloride having a mass of 1.11 g may be determined using the molar mass of calcium chloride, which we already know. The following is the formula to get the number of moles:
Molar mass divided by mass equals a mole.Substituting the values we know, we get:
moles of CaCl2 = 1.11 g / 110.98 g/mol = 0.01 mol
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30 POINTS HELP FAST
A scientist is using potassium-40, which is a radioactive isotope of potassium, to find the absolute age of a fossil by radiometric dating. The scientist determines that about three-fourths of the original potassium-40 atoms in the fossil now remain in the fossil. What additional information is necessary for the scientist to determine the absolute age of the fossil? Question 2 options: the half-life of potassium-40 the identity of an index fossil the atomic mass of potassium-40 the total mass of the fossil "choose a b c or d"
The additional information necessary is: "the half-life of potassium-40." for the scientist to determine the absolute age of the fossil.
What is Radiometric Dating?Radiometric dating is a method used to determine the absolute age of rocks and fossils based on the decay of radioactive isotopes. The rate of decay of a radioactive isotope is measured in terms of its half-life, which is the time it takes for half of the original parent atoms to decay into daughter atoms.
In this case, the scientist needs to know the half-life of potassium-40 in order to calculate the absolute age of the fossil. By knowing the half-life of potassium-40, the scientist can determine how much time has elapsed since the fossil was formed based on the proportion of parent and daughter atoms present in the fossil.
Therefore, the correct answer is: the half-life of potassium-40.
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which statement is true about a chemical reaction at equilibrium? select one: the forward reaction has reached completion. the mass of the products is equal to the mass of the reactants. the reverse reaction has reached completion. the forward reaction rate is equal to the reverse reaction rate.
The statement which is true about a chemical reaction at equilibrium is "the forward reaction rate is equal to the reverse reaction rate". This is because no change in concentration is observed at equilibrium.
What is Equilibrium?Equilibrium is defined as the point at which the forward reaction rate is equal to the reverse reaction rate. At this point, the concentration of reactants and products does not change over time, which means that the reaction has reached a steady state. The other options listed in the question are not true about a chemical reaction at equilibrium. The forward reaction does not reach completion, as the reaction is ongoing, and the reverse reaction also does not reach completion.
The mass of the products may or may not be equal to the mass of the reactants, depending on the reaction in question. However, this is not a defining characteristic of a chemical reaction at equilibrium. A chemical reaction at equilibrium is defined by the fact that the forward and reverse reaction rates are equal. This can be represented using the equilibrium constant (K), which is equal to the ratio of the product concentrations to the reactant concentrations raised to their respective stoichiometric coefficients. At equilibrium, the value of K does not change over time.
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A 32.0 mL sample of hydrogen is collected over water at 20.0 degrees Celsius and 750.0 torr. What is the volume of the dry gas at STP? (Vapor pressure of water at 20 degrees C = 17.5 torr)
The volume of the dry gas at STP when a 32.0 mL sample of hydrogen is collected over water at 20.0 degrees Celsius and 750.0 torr is 31.1 mL.
What is the formula to calculate the volume of the dry gas at STP?There is a formula used to calculate the volume of dry gas at STP given a sample of hydrogen gas collected over water at a specific temperature and pressure, which is as follows:
Vd = Vw - Vh2o
Vd = volume of the dry gas, Vw = volume of the wet gas, Vh2o = vapor pressure of water at a given temperature
The next thing is to calculate Vw which is the volume of the wet gas.
Vw = Vtotal - Vh2o
Vtotal = total volume of the gas collected, Vh2o = volume of the water collected
In the question, the volume of the hydrogen gas collected over water at 20.0 degrees Celsius and 750.0 torr is 32.0 mL.
Vh2o = P × V / R × T
where, P = pressure = 17.5 torr, V = volume of the water collected = 0.0 mL (not given)
Vh2o = 0.0 torr × mL / 62.36 (L•torr/K•mol) × (293.15 K) = 0.0 mL
The total volume of the gas collected, Vtotal = Vh2o + Vw + Vh2 = 0.0 mL + 32.0 mL + 0.0 mL = 32.0 mL
Now we can calculate Vw as follows: Vw = Vtotal - Vh2o = 32.0 mL - 0.0 mL = 32.0 mL
Finally, we can calculate the volume of the dry gas at STP: Vd = Vw - Vh2o
Vd = 32.0 mL - 0.9 mL ≈ 31.1 mL
Therefore, the volume of the dry gas at STP when a 32.0 mL sample of hydrogen is collected over water at 20.0 degrees Celsius and 750.0 torr is 31.1 mL.
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