Question 1

How does a catalyst increase the rate of a reaction?

Accepted Answer

A) It lowers the activation energy. 
B) It is neither created nor consumed in a reaction. 
C) It has nothing to do with the rate of reaction. 
D) It increases the energy difference between the reactants and products. 
E) It raises the activation energy of the reactants,which makes the reaction proceed faster. 
A) It lowers the activation energy. 
B) It is neither created nor consumed in a reaction. 
C) It has nothing to do with the rate of reaction. 
D) It increases the energy difference between the reactants and products. 
E) It raises the activation energy of the reactants,which makes the reaction proceed faster.

Question 2

How many grams of water can be produced from the combination of 25.0 grams of hydrogen and 225 grams of oxygen?

Accepted Answer

A) 250 grams 
B) 225 grams 
C) 200 grams 
D) 25 grams 
A) 250 grams 
B) 225 grams 
C) 200 grams 
D) 25 grams

Question 3

Which has the greatest number of molecules?

Accepted Answer

A) 28 g of nitrogen, $\mathrm { N } _ { 2 }$ 
B) 32 g of oxygen, $\mathrm { O } _ { 2 }$ 
C) 32 g of methane,C $\mathrm { H } _ { 4 }$ 
D) 38 g of fluorine, $\mathrm { F } _ { 2 }$ 
A) 28 g of nitrogen, $\mathrm { N } _ { 2 }$ 
B) 32 g of oxygen, $\mathrm { O } _ { 2 }$ 
C) 32 g of methane,C $\mathrm { H } _ { 4 }$ 
D) 38 g of fluorine, $\mathrm { F } _ { 2 }$

Question 4

Entropy helps to explain

Accepted Answer

A) the forward motion of time. 
B) the cause of a chemical reaction. 
C) sunsets. 
D) photosynthesis. 
E) All of the above. 
A) the forward motion of time. 
B) the cause of a chemical reaction. 
C) sunsets. 
D) photosynthesis. 
E) All of the above.

Question 5

Carefully examine the following reaction sequence for the catalytic formation of ozone,O3,from molecular oxygen, $\mathrm { O } _ { 2 }$ .Which chemical compound is behaving as the catalyst? $\mathrm { O } _ { 2 }$ + 2 NO ? 2 N $\mathrm { O } _ { 2 }$ 2 N $\mathrm { O } _ { 2 }$ ? 2 NO + 2 O 2 O + 2 $\mathrm { O } _ { 2 }$ ? 2 $\mathrm { O } _ { 3 }$

Accepted Answer

A) nitrogen monoxide,NO 
B) nitrogen dioxide,N $\mathrm { O } _ { 2 }$ 
C) oxygen, $\mathrm { O } _ { 2 }$ 
D) atomic oxygen,O 
A) nitrogen monoxide,NO 
B) nitrogen dioxide,N $\mathrm { O } _ { 2 }$ 
C) oxygen, $\mathrm { O } _ { 2 }$ 
D) atomic oxygen,O

Question 6

What coefficient is needed in front of the O2 molecule to balance the following equation? 2 $\mathrm { C } _ { 4 }$ $\mathrm { H } _ { 10 }$ (g)+ ________ $\mathrm { O } _ { 2 }$ (g)? 8 $\mathrm { CO } _ { 2 }$ (g)+ 10 $\mathrm { H } _ { 2 }$ O (l)

Accepted Answer

A) 8 
B) 13 
C) 5 
D) 1 
A) 8 
B) 13 
C) 5 
D) 1

Question 7

Why is heat often added to chemical reactions performed in the laboratory?

Accepted Answer

A) to allow a greater number of reactants to pass over the activation energy 
B) to increase the rate at which reactant collide 
C) to compensate for the natural tendency of energy to disperse 
D) all of the above 
A) to allow a greater number of reactants to pass over the activation energy 
B) to increase the rate at which reactant collide 
C) to compensate for the natural tendency of energy to disperse 
D) all of the above

Question 8

What is the number of moles of H2O produced if you combust 0.5 mole of CH4 according to the following balanced equation? CH4 + 2 O2 → CO2 + 2 H2O

Accepted Answer

A) 2 moles 
B) 4 moles 
C) 6 moles 
D) 8 moles 
E) 1 mole 
A) 2 moles 
B) 4 moles 
C) 6 moles 
D) 8 moles 
E) 1 mole

Question 9

Which of the following statements about ozone is true?

Accepted Answer

A) Ozone in the stratosphere is beneficial. 
B) Ozone in the troposphere is a pollutant. 
C) Ozone is generated from photochemical reactions of hydrocarbons. 
D) none of the above 
E) both a and b 
A) Ozone in the stratosphere is beneficial. 
B) Ozone in the troposphere is a pollutant. 
C) Ozone is generated from photochemical reactions of hydrocarbons. 
D) none of the above 
E) both a and b

Question 10

What role does entropy play in chemical reactions?

Accepted Answer

A) The entropy determines how much product will actually be produced. 
B) The entropy change determines whether the reaction will be exothermic or endothermic. 
C) The entropy change determines whether the reaction will occur spontaneously or not. 
D) The entropy change determines whether or not the chemical reaction is favorable. 
A) The entropy determines how much product will actually be produced. 
B) The entropy change determines whether the reaction will be exothermic or endothermic. 
C) The entropy change determines whether the reaction will occur spontaneously or not. 
D) The entropy change determines whether or not the chemical reaction is favorable.

Question 11

If it takes 200 golf balls to equal the mass of four bowling balls,what is the relative mass of bowling balls to golf balls?

Accepted Answer

A) 1/50 
B) 1/20 
C) 20 times 
D) 100 times 
E) 6.022 × 1023  
A) 1/50 
B) 1/20 
C) 20 times 
D) 100 times 
E) 6.022 × 1023

Question 12

The portion of the atmosphere that filters out 95 percent of the incident UV radiation is the

Accepted Answer

A) ozone layer. 
B) stratosphere. 
C) troposphere. 
D) aerosol layer. 
E) particulates. 
A) ozone layer. 
B) stratosphere. 
C) troposphere. 
D) aerosol layer. 
E) particulates.

Question 13

How many grams of water can be produced by the combination of 8 grams of oxygen and 8 grams of hydrogen?

Accepted Answer

A) 16 grams 
B) 10 grams 
C) 9 grams 
D) 8 grams 
A) 16 grams 
B) 10 grams 
C) 9 grams 
D) 8 grams

Question 14

According to the following balanced chemical equation,if you want to generate two moles of H2O how many grams of O2 do you need? 2 H2 + O2 → 2 H2O

Accepted Answer

A) 32 
B) 16 
C) 8 
D) 4 
E) 6.022 × 1023 
A) 32 
B) 16 
C) 8 
D) 4 
E) 6.022 × 1023

Question 15

What is the number of moles of H2O produced if you combust one mole of CH4 according to the following balanced equation? CH4 + 2 O2 → CO2 + 2 H2O

Accepted Answer

A) 2 moles 
B) 4 moles 
C) 6 moles 
D) 8 moles 
E) 1 mole 
A) 2 moles 
B) 4 moles 
C) 6 moles 
D) 8 moles 
E) 1 mole

Question 16

Given that the bond energy of N2 is 946 kJ/mole,the bond energy of O2 is 498 kJ/mole and the NO bond energy is 631 kJ/mole,how much energy is required to react 1 mole of nitrogen molecules according to the following reaction? N2 + O2 → 2 NO

Accepted Answer

A) 182 kJ 
B) -182 kJ 
C) 813 kJ 
D) -813 kJ 
E) 2075 kJ 
A) 182 kJ 
B) -182 kJ 
C) 813 kJ 
D) -813 kJ 
E) 2075 kJ

Question 17

You are given two samples of elements,and each sample has a mass of 10 grams.If the number of atoms in each of these samples is the same,what must be true of the two elements?

Accepted Answer

A) The density of the two elements are the same. 
B) The elements are likely be located in the same position in the periodic table. 
C) Their spectral patterns will likely be identical. 
D) all of the above 
A) The density of the two elements are the same. 
B) The elements are likely be located in the same position in the periodic table. 
C) Their spectral patterns will likely be identical. 
D) all of the above

Question 18

What is the formula mass of sulfur dioxide,S $\mathrm { O } _ { 2 }$ ?

Accepted Answer

A) about 16 amu 
B) about 32 amu 
C) about 60 amu 
D) about 64 amu 
A) about 16 amu 
B) about 32 amu 
C) about 60 amu 
D) about 64 amu

Question 19

The chlorinated fluorocarbons molecules are acting as a(n)________ by converting hundreds of thousands of molecules before they are inactivated.

Accepted Answer

A) catalyst 
B) aerosol 
C) active site 
D) acid 
E) base 
A) catalyst 
B) aerosol 
C) active site 
D) acid 
E) base

Question 20

What is the environmentally unfriendly component of chlorinated fluorocarbons that ultimately damages ozone?

Accepted Answer

A) chlorine atoms 
B) fluorine atoms 
C) carbon atoms 
D) molecular fragments of carbon and fluorine 
E) all of the above 
A) chlorine atoms 
B) fluorine atoms 
C) carbon atoms 
D) molecular fragments of carbon and fluorine 
E) all of the above

Exam 17: How Chemicals React

How does a catalyst increase the rate of a reaction?

How many grams of water can be produced from the combination of 25.0 grams of hydrogen and 225 grams of oxygen?

Which has the greatest number of molecules?

Entropy helps to explain

What coefficient is needed in front of the O2 molecule to balance the following equation? 2 C4\mathrm { C } _ { 4 }C4​ H10\mathrm { H } _ { 10 }H10​ (g)+ ________ O2\mathrm { O } _ { 2 }O2​ (g)? 8 CO2\mathrm { CO } _ { 2 }CO2​ (g)+ 10 H2\mathrm { H } _ { 2 }H2​ O (l)

Why is heat often added to chemical reactions performed in the laboratory?

What is the number of moles of H2O produced if you combust 0.5 mole of CH4 according to the following balanced equation? CH4 + 2 O2 → CO2 + 2 H2O

Which of the following statements about ozone is true?

What role does entropy play in chemical reactions?

If it takes 200 golf balls to equal the mass of four bowling balls,what is the relative mass of bowling balls to golf balls?

The portion of the atmosphere that filters out 95 percent of the incident UV radiation is the

How many grams of water can be produced by the combination of 8 grams of oxygen and 8 grams of hydrogen?

According to the following balanced chemical equation,if you want to generate two moles of H2O how many grams of O2 do you need? 2 H2 + O2 → 2 H2O

What is the number of moles of H2O produced if you combust one mole of CH4 according to the following balanced equation? CH4 + 2 O2 → CO2 + 2 H2O

Given that the bond energy of N2 is 946 kJ/mole,the bond energy of O2 is 498 kJ/mole and the NO bond energy is 631 kJ/mole,how much energy is required to react 1 mole of nitrogen molecules according to the following reaction? N2 + O2 → 2 NO

You are given two samples of elements,and each sample has a mass of 10 grams.If the number of atoms in each of these samples is the same,what must be true of the two elements?

What is the formula mass of sulfur dioxide,S O2\mathrm { O } _ { 2 }O2​ ?

The chlorinated fluorocarbons molecules are acting as a(n)________ by converting hundreds of thousands of molecules before they are inactivated.

What is the environmentally unfriendly component of chlorinated fluorocarbons that ultimately damages ozone?

Patterns of Motion and Equilibrium

Newtons Laws of Motion

Momentum and Energy

Gravity, Projectiles, and Satellites

Fluid Mechanics

Thermal Energy and Thermodynamics

Heat Transfer and Change of Phase

Static and Current Electricity

Magnetism and Electromagnetic Induction

Waves and Sound

Light

Atoms and the Periodic Table

The Atomic Nucleus and Radioactivity

Elements of Chemistry

How Atoms Bond and Molecules Attract

Mixtures

Two Classes of Chemical Reactions

Organic Compounds

Rocks and Minerals

Plate Tectonics and Earths Interior

Shaping Earths Surface

Geologic Time - Reading the Rock Record

The Oceans, Atmosphere, and Climatic Effects

Driving Forces of Weather

The Solar System

Stars and Galaxies

The Structure of Space and Time

Prologue: The Nature of Science

Filters

What coefficient is needed in front of the O₂ molecule to balance the following equation? 2 $\mathrm { C } _ { 4 }$ $\mathrm { H } _ { 10 }$ (g)+ ________ $\mathrm { O } _ { 2 }$ (g)? 8 $\mathrm { CO } _ { 2 }$ (g)+ 10 $\mathrm { H } _ { 2 }$ O (l)

What is the number of moles of H₂O produced if you combust 0.5 mole of CH₄ according to the following balanced equation? CH₄ + 2 O₂ → CO₂ + 2 H₂O

According to the following balanced chemical equation,if you want to generate two moles of H₂O how many grams of O₂ do you need? 2 H₂ + O₂ → 2 H₂O

What is the number of moles of H₂O produced if you combust one mole of CH₄ according to the following balanced equation? CH₄ + 2 O₂ → CO₂ + 2 H₂O

Given that the bond energy of N₂ is 946 kJ/mole,the bond energy of O₂ is 498 kJ/mole and the NO bond energy is 631 kJ/mole,how much energy is required to react 1 mole of nitrogen molecules according to the following reaction? N₂ + O₂ → 2 NO

What is the formula mass of sulfur dioxide,S $\mathrm { O } _ { 2 }$ ?