Answer: B. It must show that the mass of each element involved is conserved by a chemical reaction.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The correct statement why a chemical equation must be balanced is It must show that the mass of each element involved is conserved by a chemical reaction.
Answer:
B. It must show that the mass of each element involved is conserved
by a chemical reaction.
Explanation:
a p e x, just took the quiz
Given the balanced equation representing a
reaction:
02 → 0 + 0
What occurs during this reaction?
Answer:
A molecule of oxygen breaks into two atoms of oxygen showing that the bond is being broken. When bonds break, energy is absorbed and when bonds are formed energy is released. Hence, the answer to this question is (A).
Explanation:
What rock forms from magma oozing onto the surface?
a. Igneous rock
b. Metamorphic rock
C. Sedimentary rock
d. Lava rock
5. Given the formula of a substance:
H Hн H
IT
C-C-C=C
1
H
H
What is the total number of shared electrons in a
molecule of this substance?
A) 22
B) 11
C) 9
D) 6
A) 22
In a single bond one pair of electrons is shared, with one electron being contributed from each of the atoms. Double bonds share two pairs of electrons and triple bonds share three pairs of electrons. Bonds sharing more than one pair of electrons are called multiple covalent bonds.In the given molecule:
There are total 7 single bonds and 2 double bonds.
As we know, In a single bond one pair of electrons is shared and double bonds share two pairs of electrons.
Thus,
Total number of shared electrons in a molecule= 7*2+2*4=14+8=22
So, total number of shared electrons in a molecule is 22.
Therefore, option A) is correct.
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number of molecules in lithium sulfate Li2So4
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.
Respiration occurs at the cellular level
truebor false?
the answer is : False
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A chemist working as a safety inspector finds an unmarked bottle in a lab cabinet. A note on the door of the cabinet says the cabinet is used to store bottles of carbon tetrachloride, diethylamine, methyl acetate, ethanolamine, and dimethyl sulfoxide.
The chemist plans to try to identify the unknown liquid by measuring the density and comparing to known densities. First, from his collection of Material Safety Data Sheets (MSDS), the chemist finds the following information:
Liquid Density
Tetrahydrofuran 0.89·gcm^−3
Carbon tetrachloride 1.6·gcm^−3
Pentane 0.63·gcm^−3
Dimethyl sulfoxide 1.1·gcm^−3
Acetone 0.79·gcm^−3.
Next, the chemist measures the volume of the unknown liquid as 0.852L and the mass of the unknown liquid as 938.g . Calculate the density of the liquid.
Answer: The density of the liquid is [tex]1.10g/cm^3[/tex]
Explanation:
Density is defined as the mass contained per unit volume.
[tex]Density=\frac{mass}{Volume}[/tex]
Given : Mass of the unknown liquid = 938 grams
Volume of the unknown liquid = [tex]0.852L=852cm^3[/tex] [tex](1L=1000cm^3[/tex]
Putting in the values we get:
[tex]Density=\frac{938g}{852cm^3}[/tex]
[tex]Density=1.10g/cm^3[/tex]
Thus the density of the liquid is [tex]1.10g/cm^3[/tex] and the liquid is dimethyl sulfoxide.
How many particles are in 9.58 x 1023 of potassium sulfate (K2SO4)? (5.77 x 1047 particles)
Answer:
[tex]5.77x10^{47}particles.[/tex]
Explanation:
Hello!
In this case, since we are given 9.58x10²³ moles of potassium sulfate, it is possible to compute the particles according to the Avogadro's number:
6.022x10²³
As shown below:
[tex]9.58x10^{23}mol*\frac{6.022x10^{23}}{1mol}\\\\5.77x10^{47}particles.[/tex]
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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.
[tex]{ }[/tex]
[tex]\small\sf\:\:\:\:\:\:\:\:{:}\:\Longrightarrow{\bold{\pink{\sf{Thomson's \:model}}}}[/tex]
3. Explain what would happen to the digestion process if enzymes were not present. SC.6.L.14.5
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
Answer: https://brainly.com/question/2426371
Explanation: Someone already answered this, click the link. YW! :))
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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A cell biologist measures the volume of a bacteria cell. The volume is 6.027x10-10 L. What is the volume in picoliters? Write your answer as a decimal.
pL
Answer:
Volume of bacteria cell into Pico liters = 60.27 Pico liters
Explanation:
Given:
Volume of bacteria cell = 6.027 x 10⁻¹⁰ L
Find:
Volume of bacteria cell into Pico liters
Computation:
1 L = 10¹² Pico liters
So,
Volume of bacteria cell = 6.027 x 10⁻¹⁰ L
Volume of bacteria cell = 6.027 x 10⁻¹⁰ x 10¹² Pico liters
Volume of bacteria cell into Pico liters = 60.27 Pico liters
mathdrrggeszdrsz seer r-
Answer:
130!!
Explanation:
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.
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:
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.
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.
(22 points) please please help me thanks so much
Answer:
d
Explanation:
Answer:
hopen it helps soo much thanks for the points
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
Learn more on Graham's law of effusion here;
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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
What is the mass of 8.56 x 10^23 formula units of BaBr2? (3 sig figs in your answer)
296 g BaBr₂
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableMolesAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
[Given] 8.56 × 10²³ formula units BaBr₂
[Solve] grams BaBr₂
Step 2: Identify Conversions
Avogadro's Number
[PT] Molar Mass of Ba - 137.33 g/mol
[PT] Molar Mass of Br - 35.45 g/mol
Molar Mass of BaBr₂ - 137.33 + 2(35.45) = 208.23 g/mol
Step 3: Convert
[DA} Set up: [tex]\displaystyle 8.56 \cdot 10^{23} \ formula \ units \ BaBr_2(\frac{1 \ mol \ BaBr_2}{6.022 \cdot 10^{23} \ formula \ units \ BaBr_2})(\frac{208.23 \ g \ BaBr_2}{1 \ mol \ BaBr_2})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 295.99 \ g \ BaBr_2[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
295.99 g BaBr₂ ≈ 296 g BaBr₂
Thank you agenthammerx for helping me with this question!
Answer:
296 g BaBr₂
General Formulas and Concepts:
Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction
Left to Right
Chemistry
Atomic Structure
Reading a Periodic Table
Moles
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
Stoichiometry
Using Dimensional Analysis
Explanation:
Step 1: Define
[Given] 8.56 × 10²³ formula units BaBr₂
[Solve] grams BaBr₂
Step 2: Identify Conversions
Avogadro's Number
[PT] Molar Mass of Ba - 137.33 g/mol
[PT] Molar Mass of Br - 35.45 g/mol
Molar Mass of BaBr₂ - 137.33 + 2(35.45) = 208.23 g/mol
Step 3: Convert
[DA} Set up:
[DA] Multiply/Divide [Cancel out units]:
Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
295.99 g BaBr₂ ≈ 296 g BaBr₂
Which phrase describes air density?
increases as altitude increases
equals mass divided by volume
pushes molecules in one direction
exerts less pressure as it increases
If you answer I love you
Answer:B equals mass divided by volume
Explanation:I got hacks :)
Answer:
Which phrase describes air density? well b
increases as altitude increases
equals mass divided by volume
pushes molecules in one direction
exerts less pressure as it increases
Explanation:
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Which statement best describes how matter and energy is cycled through the ecosystem?
A. Energy is recycled in an ecosystem, but matter is not recycled.
B. Matter and energy are both cycled throughout an ecosystem, and much of the energy at each level is changed to heat energy.
C. Energy is gained in each level on the energy pyramid, and matter is lost in an ecosystem.
D. Matter and energy are the same.
D. Matter and energy are the same.
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.
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)
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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
What causes a ionic bond to occur
Answer:
when the valence (outermost) electrons of one atom are transferred permanently to another atom
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