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Chemical Reactions

Total questions: 26

Worksheet time: 1hrs 9mins

Name
Class
Date
1.
In a chemical equation, is it true that -
a)
the reactant side and product side can have different numbers of atoms for each element
b)
there can be different elements on the reactant side and the product side
c)
an element or compound must be accompanied by a phase change
d)
the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made
2.
Which of the following models best demonstrates a balanced chemical equation?
a)
F
b)
G
c)
H
d)
J
3.
The formula below represents the most common carbohydrate known as glucose. Which information can be determined from the chemical formula?
C6H12O6
a)
The structural arrangement of the atoms in a glucose molecule
b)
The color of a glucose molecule
c)
The size of a glucose molecule
d)
The number of atoms of each element in a glucose molecule
4.
For an investigation a student poured a blue solution of CuSO4 into a beaker. The student placed a shiny, silver-colored strip of zinc metal in the solution and observed the changes.
The student inferred that a chemical reaction occurred. What evidence supports this inference?
a)
A dark solid formed on the zinc metal.
b)

The zinc metal remained silver-colored and shiny
c)
The CuSO4 solution turned blue when the zinc metal was added.
d)
None of these
5.
Which of the following equations demonstrates an actual chemical reaction that forms a new substance?
a)
A
b)
B
c)
C
d)
D
6.
The chemical formula for glucose, a simple sugar, is C6H12O6. The formula for ethanol is C2H6O. What accounts for the differences in these compounds?
a)
The elements that make up glucose are different than the elements that make up ethanol
b)
The ratio of the elements is different in ethanol than in glucose
c)
The chemical properties of the elements are different in glucose and ethanol
d)
Glucose has more elements than the ethanol
7.
Which of these formulas contain equal numbers of nitrogen atoms?
a)
Formulas I and III
b)
Formulas I and IV
c)
Formulas II and III
d)
Formulas I, II, and V
8.
The reactants are on the left side of the chemical equation.
a)
True
b)
False
9.
Two clear colorless solutions were combined.
The student observed that the temperature changed from 25 •C to 23 •C when the solutions were combined and that a white substance rapidly formed and settled to the bottom of the container. What most likely happened to produce these results?
a)
One of the original compounds came out of solution
b)
The solutions reacted chemically
c)
Some of the water froze into ice crystals
d)
Rapid evaporation of water occurred, leaving a solid
10.
The equation below represents a chemical reaction that occurs in living cells. How many atoms are represented in the reactants of this equation?
a)
6
6
b)
12
12
c)
24
24
d)
36
36
11.
In which of these compounds are there twice as many oxygen atoms as hydrogen atoms?
a)
H3PO4
b)
H2SO4
c)
HCIO3
d)
H20
12.

How many atoms in all are in a molecule of serotonin?

C10H12N2O

a)
22
b)
24
c)
25
d)
4
13.
Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?
a)
The shape of the coal changes
b)
Oxygen is present
c)
A new substance is produced
d)
Coal is made up of more than one element
14.
All of the following reactions are correctly balanced except-
a)
A
b)
B
c)
C
d)
D
15.
What is the mass of H2O in the reaction above?
a)
70.01
b)
24.11
c)
21.44
d)
48.22
16.
Which of the following BEST describes a chemical reaction?
a)
A compound is crushed into a fine powder.
b)
Atoms break apart into even smaller particles.
c)
Existing electron bonds creak and reattach to other atoms
d)
Molecules move faster until they fly apart from each other
17.
A scientist performed four investigations using eight different liquids. In each investigation, the scientist combined two of the liquids under a fume hood and recorded observations in the table below.In which investigation is it least likely that the liquids reacted chemically?
a)
1
b)
2
c)
3
d)
4
18.

In a ___________change, a substance changes into a different substance.

a)

Physical

b)

Chemical

19.

Which of these is NOT a sign that a chemical change has occurred?

a)

A loss of transparency

b)

An unexpected color change

c)

A temperature change

d)

The formation of a precipitate

20.

The Law of Conservation of Mass states

a)

that matter exists in all states and reacts the same

b)

that matter can only be changed into new substances by introducing a catalyst

c)

that matter exists in the same state throughout any chemical change

d)

that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants

21.

How many Al atoms are in this compound? 4Al2O3

a)

2

b)

8

c)

6

d)

4

22.

How many F atoms are in this compound?

6MgF2

a)

2

b)

6

c)

8

d)

12

23.

a copper penny turning greenish after a few years.

a)

Physical change

b)

Chemical change

24.

An gel ice pack getting cold after you put it in the freezer for an hour.

a)

Chemical change

b)

Physical change

25.

Which of the following IS a physical change?

a)

Getting a haircut

b)

Rusty metal

c)

sour milk

d)

A compound

26.

___________________ are the elements or compounds that leave (are formed in) a chemical reaction.

a)

Polymers

b)

Bonds

c)

Reactants

d)

Products

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