Answer:
A. When two aqueous solutions are mixed, a precipitate is formed.
Explanation:
The precipitate (a solid substance that falls from the liquid) is the result of a chemical reaction taking place between the liquids.
The other three answer choices are indicative of physical changes (temperature change, phase change, color change).
When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.
Hence, option A is correct answer.
What is Chemical change ?Chemical change are those changes in which substance changes chemical composition. These changes are permanent changes. In chemical change new substances formed and in chemical change substances can not get back into its original form. It is irreversible change.
What is Physical change ?Physical changes are those changes in which substance changes physical properties only. Properties like temperature, pressure, shape, color, size, state (solid, liquid and gas). These changes are temporary in nature. In physical change no new substances formed. It is reversible change.
Now, check all the options one by one:
Option (A): When two aqueous solutions are mixed, a precipitate is formed is a chemical change. Since precipitation indicate a chemical reaction (that is double displacement reaction).
Option (B): As ammonium nitrate dissolved in water causes the temperature to decrease is a physical change because heat energy is absorbed here and it is a endothermic reaction.
Option (C): Alcohol evaporates when left in an open container is a physical change because evaporation is a physical change as it changes the state from liquid state to gas state.
Option (D): Water is added to blue copper (II) chloride solution. The resulting mixture if lighter blue in color is a physical change as properties like change in color is physical change.
Thus, from above conclusion we can say that When two aqueous solutions are mixed, a precipitate is formed indicates that a chemical change has occurred.
Hence, option A is correct answer.
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Go to the Phase Changes tab. Select the particular molecule, and set the temperature to the given values by using the stove to increase or decrease the temperature. Increase the pressure of the cylinder by moving the lid of the cylinder down with the help of the finger. The pressure of the cylinder is indicated by the pressure gauge on the top left corner of the simulation. On the right-hand side of the simulation is the phase diagram for the molecule.
As the molecules collide on the walls of the cylinder, the pressure of the cylinder does not remain constant; it fluctuates slightly as indicated by the gauge.
In the phase diagram, observe the red point. When a particular molecule is selected, set the temperature and pressure condition to the required value. Observe the position of the red point on the phase diagram when the pressure reaches approximately near the required value.
Which of the following conditions will result in the formation of a supercritical fluid?
Check all that apply.
1. Oxygen at 100 K and no pressure
2. Argon at 160 K and approximately 6 atm pressure
3. Water at 294 K and approximately 1 atm pressure
4. Neon at 32 K and approximately 1 atm pressure
5. Neon at 50 K and approximately 10 atm pressure
6. Water at 894 K and approximately 20 atm pressure
7. Argon at 100 K and no pressure
8. Oxygen at 194 K and approximately 2 atm pressure
Answer:
2. Argon at 160K and approximately 6 atm pressure
5. Neon at 50K and approximately 10 atm pressure
6. Water at 894 K and approximately 20 atm pressure
8. Oxygen at 194K and approximately 2 atm pressure
Explanation:
Super critical fluid is formed when temperature rises beyond critical point. The state of molecules can be liquid or gas. The pressure should be above the certain level with an introduction of different gases at minimum of 2 atm pressure.
whose model was discarded as a result of Rutherford's model?
A Dalton's model
B Thomson's model
C Bohr's model
D Quantum's model
Answer:
A. Dalton's model
Explanation:
Dalton's model was discarded as a result of Rutherford's model.
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[tex]\small\sf\:\:\:\:\:\:\:\:{:}\:\Longrightarrow{\bold{\pink{\sf{Thomson's \:model}}}}[/tex]
Scientists have been classifying living organisms for centuries. In the 1970s, organisms were classified in a five-kingdom
classification scheme. However, two decades later, organisms called Archaebacteria were discovered. This led to a three-domain
system of classification that combined some of the previous five-kingdom schemes.
What does this change in classification methods demonstrate?
Answer:
Classification is important because it allows scientists to identify, group, and properly name organisms via a standardized system (Linnaeus Taxonomy); based on similarities found in the organisms DNA/RNA (genetics), Adaptations (Evolution), and Embryonic development (Embryology) to other known organisms to better.
Hope I helped!!
The five kingdoms of classifications were animalia, plant, fungi, protista and monera. Later Archaebacteria was discovered and this led to the 3 kingdom classification animalia, plantae and protista.
What is biological classification?There are different classifications for living things based on their nature, body and origin. The kingdom animalia includes all the animals including human beings.
Kingdom plante includes all the plants and kingdom fungi, protista and monera are of microbes. Later the discovery and study of Archaebacteria proved that they exhibit similar body type and functions as bacterias.
After that, scientists turned into 3 kingdom classification, where all the prokaryotic organisms including protists, monera and fungi classified as one. The evolutional changes originated in them made this classification.
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What causes a ionic bond to occur
Answer:
when the valence (outermost) electrons of one atom are transferred permanently to another atom
PLZ HELP URGENT!!!!!
Answer:
A fluke because it is an vertebrae
Explanation:
Which body system provides protection of the brain and the spinal cord?
Answer:
The bones of the skull and spinal column
Explanation:
The central nervous system is better protected than any other system or organ in the body. Its main line of defense is the bones of the skull and spinal column, which create a hard physical barrier to injury.
Answer:
The Central Nervous System (CNS)
Hydrofluoric acid and Water react to form fluoride anion and hydronium cation, like this HF(aq) + H_2O(l) rightarrow F(aq) + H_3O^+ (aq) At a certain temperature, a chemist finds that a 5.6 L reaction vessel containing an aqueous solution of hydrofluoric acid, water, fluoride anion, and hydronium cation at equilibrium has the following composition: Calculate the value of the equilibrium constant K_C for this reaction. Round your answer to 2 significant digits. K_C =
Answer:
Kc = 1.09x10⁻⁴
Explanation:
HF = 1.62g
H₂O = 516g
F⁻ = 0.163g
H₃O⁺ = 0.110g
To solve this question we need to find the moles of each reactant in order to solve the molar concentration of each reactan and replacing in the Kc expression. For the reaction, the Kc is:
Kc = [H₃O⁺] [F⁻] / [HF]
Because Kc is defined as the ratio between concentrations of products over reactants powered to its reaction coefficient. Pure liquids as water are not taken into account in Kc expression:
[H₃O⁺] = 0.110g * (1mol /19.01g) = 0.00579moles / 5.6L = 1.03x10⁻³M
[F⁻] = 0.163g * (1mol /19.0g) = 0.00858moles / 5.6L = 1.53x10⁻³M
[HF] = 1.62g * (1mol /20g) = 0.081moles / 5.6L = 0.0145M
Kc = [1.03x10⁻³M] [1.53x10⁻³M] / [0.0145M]
Kc = 1.09x10⁻⁴3. Explain what would happen to the digestion process if enzymes were not present. SC.6.L.14.5
Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. In the first step, nitrogen and hydrogen react to form ammonia: (g) (g) (g) In the second step, ammonia and oxygen react to form nitric acid and water: (g) (g) (g) (g) Calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions.
Answer:
Overall enthalpy change for the formation of one mole nitric acid from nitrogen, hydrogen and oxygen, ΔH = -376 KJ
Note: the question is incomplete. The complete question is given below:
Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. In the first step, nitrogen and hydrogen react to form ammonia: N₂(g) + 3H₂(g) → 2NH₃(g) ΔH = -92. kJ In the second step, ammonia and oxygen react to form nitric acid and water: NH3(g) + 2O2(g) → HNO3(g) + H2O(g) ΔH = -330. kJ Calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. Round your answer to the nearest kJ.
Explanation:
From Hess's law of constant heat summation, the total enthalpy change for a reaction is the sum of all changes without regard to the number of multiple stages or steps involved in a reaction.
Enthalpy is a state function as it does not depend on the path taken to attain its value. Therefore, the summation of the enthalpy changes involved in the individual steps in the reaction of the formation of nitric acid will be equal to the enthalpy change of the overall reaction step.
For the first reaction step:
N₂(g) + 3H₂(g) → 2NH₃(g) ΔH = -92. kJ
For the second reaction step:
NH₃(g) + 2O₂(g) → HNO3(g) + H2O(g) ΔH = -330. kJ
Overall reaction step:
[tex]\frac{1}{2}[/tex]N₂(g) + [tex]\frac{3}{2}[/tex]H₂(g) + 2O₂(g) → HNO₃ + H₂O ΔH = ?
The overall reaction for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen shows that the first reaction step should be divided by 2
[tex]\frac{1}{2}[/tex]N₂(g) + [tex]\frac{3}{2}[/tex]3H₂(g) → NH₃(g) ΔH = -46. kJ
Overall enthalpy change, ΔH = ΔH₁ + ΔH₂
Overall enthalpy change,ΔH = (-46 KJ) + (-330 KJ)
Overall enthalpy change,ΔH = -376 KJ
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What rock forms from magma oozing onto the surface?
a. Igneous rock
b. Metamorphic rock
C. Sedimentary rock
d. Lava rock
Oxidation-reduction (redox) reactions are reactions:______
a) in which oxidation numbers change.
b) Oxidation numbers are either real charges or formal charges which help chemists keep track of electron transfer.
c) In practice, oxidation numbers are best viewed as a bookkeeping device.
d) Oxidation cannot occur without reduction.
e) In a redox reaction the substance which is oxidized contains atoms which increase in oxidation number.
f) Oxidation is associated with electron loss (helpful mnemonic: LEO
Answer:
A. in which oxidation numbers change
Explanation:
This is because in oxidation reduction reactions or redox reactions, involves the sharing or transfer of electrons between species and the oxidation numbers changes. There is change in electrons, ions or oxidation number by gaining or lossing electrons. Increase in oxidation number is an indication of oxidation while decrease in oxidation indicate reduction.
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Using Graham's Law of Effusion, calculate
the approximate time it would take for
1.0 L of argon gas to effuse, if 1.0 L of
oxygen gas took 12.7 minutes to effuse
through the same opening.
0.070 minutes
0.89 minutes
None of the other answers
14 minutes
12 minutes
The rate of effusion of Argon here is 8.03 min
Data;
Molar mass of Oxygen = 16g/molTime for effusion of oxygen = 12.7 minMolar mass of Argon = 40g/molTime for effusion of Argon = ?Graham's Law of EffusionThis law states that the rate of effusion of a gas is inversely proportional to the square root of it's molar mass.
[tex]R \alpha \frac{1}{\sqrt{M} }[/tex]
From this,
[tex]\frac{r_1}{r_2} = \frac{\sqrt{M_2} }{M_1}[/tex]
substituting the values and solving,
[tex]\frac{R_A_r}{12.7}= \frac{\sqrt{16} }{\sqrt{40} } \\ R_A_r = \frac{12.7*\sqrt{16} }{\sqrt{40} } \\R_A_r = 8.032min[/tex]
The rate of effusion of Argon here is 8.03 min
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Please need this ASAP. Calculate the mass of lime, CaO, that would be produced from 250 tonnes of limestone,
CaCO3.
Relative atomic masses: C 12; O 16; Ca 40.
Answer:
1.4×10⁸ g of CaO
Explanation:
We'll begin by converting 250 tonnes to grams (g). This can be obtained as follow:
1 tonne = 1×10⁶ g
Therefore,
250 tonne = 250 × 1×10⁶
250 tonne = 2.5×10⁸ g
Next, the balanced equation for the reaction.
CaCO₃ —> CaO + CO₂
Next, we shall determine the mass of CaCO₃ that decomposed and the mass CaO produced from the balanced equation. This can be obtained as follow:
Molar mass of CaCO₃ = 40 + 12 + (16×3)
= 40 + 12 + 48
= 100 g/mol
Mass of CaCO₃ from the balanced equation = 1 × 100 = 100 g
Molar mass of CaO = 40 + 16
= 56 g/mol
Mass of CaO from the balanced equation = 1 × 56 = 56 g
SUMMARY:
From the balanced equation above,
100 g of CaCO₃ decomposed to produce 56 g of CaO.
Finally, we shall determine the mass of CaO produced by the decomposition of 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃. This can be obtained as follow:
From the balanced equation above,
100 g of CaCO₃ decomposed to produce 56 g of CaO.
Therefore, 2.5×10⁸ g of CaCO₃ will decompose to produce =
(2.5×10⁸ × 56)/100 = 1.4×10⁸ g of CaO.
Thus, 1.4×10⁸ g of CaO will be obtained from 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃.
You pump 100 gas particles in Basketball A and 100 gas particles in Basketball B. both basketballs are at room temperature ¿Which basketball will be more firm? ¿And Why?
Answer:
I think the answer is probably b
Whay happens regularly in fission reaction
Answer:
In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process. The fission process also releases extra neutrons, which can then split additional atoms, resulting in a chain reaction that releases a lot of energy.
Explanation:
Identify the compound that contains an ionic bond.
*
O
H20
O CO2
O Naci
O CH3CH2OH
Answer:
Nacl compound contain ionic bonds because sodium is metal and chlorin is nonmetal
What is chemistry
What is the bond type in CaO
Answer:
Ionic bond
CaO is an ionic bond. Two-element compounds are usually ionic when one element is a metal and the other is a non-metal. It is made up of one metal ion/cation(Ca^2+) and an non-metal ion/anion(O^2-).
(22 points) please please help me thanks so much
Answer:
d
Explanation:
Answer:
hopen it helps soo much thanks for the points
1) How many molecules are in 0.02 moles of beryllium iodide?
Answer:
3 grams??
Explanation:
I think this would be the answer you are looking for.
Rocks are classified as sedimentary, metamorphic, or igneous on the basis of
the
a. age of the rocks.
b. way the rocks were formed.
c. types of fossils the rocks contain.
d. number of minerals found in the rocks.
PLEASE ANSWER!! THANK YA!
Using Graham's Law of Effusion, calculate
the approximate time it would take for
1.0 L of argon gas to effuse, if 1.0 L of
oxygen gas took 12.7 minutes to effuse
through the same opening.
Answer:
I think the answer is X
Explanation:
X is a variable and variables stand for the unknown
Mg(NO3)2 soluble or insoluble?
Answer:
The chemical compound Mg(NO3)2, also known as magnesium nitrate, is very soluble, especially in water.
g The alkali metals are able to displace hydrogen readily from water. The alkaline earth metals are able to do so as well, although not nearly as vigorously. They are easily able to displace hydrogen from acid. a: Write and balance the equation for any of the alkali metals (pick your favorite!) reacting with water to form hydrogen gas and the metal's hydroxide (e.g. sodium hydroxide, potassium hydroxide). (10 points) b: Write and balance the equation for any of the alkaline earth metals (the second column on the left) reacting with hydrochloric acid to form hydrogen gas and the metal's chloride salt (e.g. magnesium chloride, calcium chloride) (10 points)
Answer:
See explanation
Explanation:
In writing a chemical reaction equation, we must ensure that it is balanced. In a balanced chemical reaction equation, the number of atoms of each element on the left hand side of the reaction equation must be equal to the number of atoms of the same atom on the right hand side of the reaction equation.
Let us now consider the reaction of NaOH with water as follows;
2Na(s) + 2H2O(l) ------> 2NaOH(aq) + H2(g)
For the reaction of Magnesium metal and HCl we have;
Mg(s) + 2HCl(aq) -------> MgCl2(aq) + H2(g)
Whoever gets these 2 right gets brainliest! :)
the first one is A covalent bond.
the second one is Answer: B Decomposition
mathdrrggeszdrsz seer r-
Answer:
130!!
Explanation:
The irreversible elementary gas-phase reaction is carried out isothermally at 305 K in a packed-bed reactor with 100 kg of catalyst. The entering pressure was 20 atm and the exit pressure is 2 atm. The feed is equal molar in A and B and the flow is in the turbulent flow regime, with F A0 10 mol/min and C A0 0.4 mol/dm 3 . Currently 80% conversion is achieved. What would be the conversion if the catalyst particle size were doubled and everything else remained the same
Answer:
0.856
Explanation:
Given data:
Feed molar rate ( Fao ) = 10 mol/min
Feed concentration ( Cao ) = 0.4 mol/dm^3
current conversion rate = 80%
Temperature = 305 K
catalyst = 100 kg
entering pressure = 20 atm
exit pressure = 2 atm
Determine the conversion if the catalyst particle size were doubled and everything else remained the same
The conversion if the catalyst particle size were doubled and other factors remains the same = 0.856
attached below is a detailed solution
2Fe + 6HCl -> 2FeCl3 + 3H2 If 7.0 moles of HCl is added to enough iron that the HCl is completely used up, how many
moles of hydrogen gas will be produced?
Answer: 3.5 moles of hydrogen gas will be produced.
Explanation:
The balanced chemical equation is:
[tex]2Fe+6HCl\rightarrow 2FeCl_3+3H_2[/tex]
As HCl gets completely used up, [tex]HCl[/tex] is the limiting reagent.
According to stoichiometry :
6 moles of [tex]HCl[/tex] produces = 3 moles of [tex]H_2[/tex]
Thus 7.0 moles of [tex]HCl[/tex] produces=[tex]\frac{3}{6}\times 7.0=3.5moles[/tex] of [tex]H_2[/tex]
Thus 3.5 moles of hydrogen gas will be produced.
When developing a question for a scientific inquiry, the question will ideally
A.
not just simply ask why.
B.
identify variables.
C.
be measurable.
D.
all of these
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Explanation: Someone already answered this, click the link. YW! :))