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Unit 4 Practice Quiz - Chemical Reactions


Matching
 
 
Match each item with the correct statement below.
a.
product
d.
balanced equation
b.
reactant
e.
skeleton equation
c.
chemical equation
 

 1. 

 a chemical equation that does not indicate relative amounts of reactants and products
 

 2. 

 a new substance formed in a chemical reaction
 

 3. 

 a starting substance in a chemical reaction
 

 4. 

 a concise representation of a chemical reaction
 

 5. 

 an equation in which each side has the same number of atoms of each element
 
 
Match each item with the correct statement below.
a.
activity series of metals
c.
combustion reaction
b.
single-replacement reaction
d.
decomposition reaction
 

 6. 

 a reaction in which a single compound is broken down into simpler substances
 

 7. 

 a reaction in which oxygen reacts with another substance, often producing heat or light
 

 8. 

 a reaction in which the atoms of one element replace the atoms of a second element in a compound
 
 
Match each item with the correct statement below.
a.
activated complex
d.
activation energy
b.
reaction rate
e.
free energy
c.
inhibitor
 

 9. 

 the minimum energy colliding particles must have in order to react
 

 10. 

 arrangement of atoms at the peak of an energy barrier
 

 11. 

 the number of atoms, ions, or molecules that react in a given time to form products
 

Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 12. 
Chemical reactions ____.
a.
occur only in living organisms
c.
only occur outside living organisms
b.
create and destroy atoms
d.
produce new substances
 

 13. 
Everyday equations describe ____.
a.
thermonuclear reactions
c.
chemical reactions
b.
everyday processes
d.
biological chemistry
 

 14. 
Chemical equations ____.
a.
describe chemical reactions
b.
show how to write chemical formulas
c.
give directions for naming chemical compounds
d.
describe only biological changes
 

 15. 
A skeleton equation does NOT show which of the following?
a.
the correct formulas of the reactants and products
b.
the reactants on the left, the products on the right
c.
an arrow connecting the reactants to the products
d.
the relative amounts of reactants and products
 

 16. 
Symbols used in equations, together with the explanations of the symbols, are shown below. Which set is correct?
a.
(g), grams
c.
(aq), dissolved in water
b.
(l), liters
d.
(s), solid product
 

 17. 
In the chemical equation Hmc017-1.jpgOmc017-2.jpg(aq) ® Hmc017-3.jpgO(l) mc017-4.jpg Omc017-5.jpg(g), the mc017-6.jpg is a ____.
a.
catalyst
c.
product
b.
solid
d.
reactant
 

 18. 
A catalyst is ____.
a.
the product of a combustion reaction
b.
not used up in a reaction
c.
one of the reactants in single-replacement reactions
d.
a solid product of a reaction
 

 19. 
Which of the following is the correct skeleton equation for the reaction that takes place when solid phosphorus combines with oxygen gas to form diphosphorus pentoxide?
a.
P(s) mc019-1.jpg Omc019-2.jpg(g) ® POmc019-3.jpg(g)
c.
P(s) mc019-7.jpg O2(g) ® Pmc019-8.jpgOmc019-9.jpg(s)
b.
P(s) mc019-4.jpg O(g) ® Pmc019-5.jpgOmc019-6.jpg(g)
d.
Pmc019-10.jpgOmc019-11.jpg(s) ® Pmc019-12.jpg(s) mc019-13.jpg Omc019-14.jpg(g)
 

 20. 
What are the coefficients that will balance the skeleton equation below?
AlClmc020-1.jpg + NaOH mc020-2.jpg Al(OH)mc020-3.jpg mc020-4.jpg NaCl
a.
1, 3, 1, 3
c.
1, 1, 1, 3
b.
3, 1, 3, 1
d.
1, 3, 3, 1
 

 21. 
What are the coefficients that will balance the skeleton equation below?
Nmc021-1.jpg + Hmc021-2.jpg mc021-3.jpg NHmc021-4.jpg
a.
1, 1, 2
c.
3, 1, 2
b.
1, 3, 3
d.
1, 3, 2
 

 22. 
When the equation Fe mc022-1.jpg Clmc022-2.jpg mc022-3.jpg FeClmc022-4.jpg is balanced, what is the coefficient for Clmc022-5.jpg?
a.
1
c.
3
b.
2
d.
4
 

 23. 
When the following equation is balanced, what is the coefficient for HCl?
Mg(s) mc023-1.jpg HCl(aq) mc023-2.jpg MgClmc023-3.jpg(aq) mc023-4.jpg Hmc023-5.jpg(g)
a.
6
c.
1
b.
3
d.
2
 

 24. 
Which of the following statements is NOT true about what happens in all chemical reactions?
a.
The ways in which atoms are joined together are changed.
b.
New atoms are formed as products.
c.
The starting substances are called reactants.
d.
The bonds of the reactants are broken and new bonds of the products are formed.
 

 25. 
Chemical equations must be balanced to satisfy ____.
a.
the law of definite proportions
c.
the law of conservation of mass
b.
the law of multiple proportions
d.
Avogadro’s principle
 

 26. 
When the equation KClOmc026-1.jpg(s) mc026-2.jpg KCl(s) + Omc026-3.jpg(g) is balanced, the coefficient of KClO3 is ____.
a.
1
c.
3
b.
2
d.
4
 

 27. 
In every balanced chemical equation, each side of the equation has the same number of ____.
a.
atoms of each element
c.
moles
b.
molecules
d.
coefficients
 

 28. 
In a combustion reaction, one of the reactants is ____.
a.
hydrogen
c.
oxygen
b.
nitrogen
d.
a metal
 

 29. 
The type of reaction that takes place when one element reacts with a compound to form a new compound and a different element is a ____.
a.
combination reaction
c.
single-replacement reaction
b.
decomposition reaction
d.
double-replacement reaction
 

 30. 
Which of the following statements is NOT correct?
a.
The only way to determine the products of a reaction is to carry out the reaction.
b.
All chemical reactions can be classified as one of five general types.
c.
Complete combustion has occurred when all the carbon in the product is in the form of carbon dioxide.
d.
A single reactant is the identifying characteristic of a decomposition reaction.
 

 31. 
Which of the following is a balanced equation representing the decomposition of lead(IV) oxide?
a.
PbOmc031-1.jpg mc031-2.jpg Pb mc031-3.jpg 2O
c.
Pbmc031-8.jpgO mc031-9.jpg 2Pb mc031-10.jpg O
b.
PbOmc031-4.jpg mc031-5.jpg Pb mc031-6.jpg Omc031-7.jpg
d.
PbO mc031-11.jpg Pb mc031-12.jpg Omc031-13.jpg
 

 32. 
Which expression represents a reaction rate?
a.
time/mass
c.
energy/time
b.
number/time
d.
time/energy
 

 33. 
Activation energy is ____.
a.
the heat released in a reaction
b.
an energy barrier between reactants and products
c.
the energy given off when reactants collide
d.
generally very high for a reaction that takes place rapidly
 

 34. 
Why does a higher temperature cause a reaction to go faster?
a.
There are more collisions per second only.
b.
Collisions occur with greater energy only.
c.
There are more collisions per second and the collisions are of greater energy.
d.
There are more collisions per second or the collisions are of greater energy.
 

 35. 
Why does a higher concentration make a reaction faster?
a.
There are more collisions per second only.
b.
Collisions occur with greater energy only.
c.
There are more collisions per second and the collisions are of greater energy.
d.
There are more collisions per second or the collisions are of greater energy.
 

 36. 
Why does a catalyst cause a reaction to proceed faster?
a.
There are more collisions per second only.
b.
The collisions occur with greater energy only.
c.
The activation energy is lowered only.
d.
There are more collisions per second and the collisions are of greater energy.
 

 37. 
What happens to a catalyst in a reaction?
a.
It is unchanged.
c.
It is incorporated into the reactants.
b.
It is incorporated into the products.
d.
It evaporates away.
 

 38. 
A catalyst works by ____.
a.
lowering the activation energy barrier
b.
shifting the equilibrium position toward the products
c.
changing the temperature of the reactants
d.
changing the particle size of the reactants
 

 39. 
The rate of a chemical reaction normally ____.
a.
decreases as temperature increases
b.
is slowed down by a catalyst
c.
increases as reactant concentration increases
d.
decreases as reactant concentration increases
 



 
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