WorksheetsChemical reactions
Total questions: 22
Worksheet time: 52mins
Name
Class
Date
1.
Which of the following is an example of a chemical change?
a)
water freezes to form ice
b)
sugar dissolves in water
c)
gasoline burns in a car engine
d)
a piece of metal expands when it is heated
2.
Which of the following is an example of a chemical change?
a)
rusting of a bicycle
b)
painting a house
c)
washing a dog
d)
tearing up a newspaper
3.
Which one shows that a chemical reaction has occurred?
a)
dissolving
b)
melting
c)
formation of a gas
d)
bending
4.
What type of change occurs when a new substance is formed that has different properties from the original substances?
a)
chemical change
b)
nuclear change
c)
physical change
d)
mutation
5.
a copper penny turning greenish after a few years.
a)
Chemical Change
b)
Physical Change
6.
In a ___________change, a substance changes into a different substance.
a)
Physical
b)
Chemical
7.
What is the BEST definition of a chemical reaction?
a)
A change in matter that produces one or more NEW substances
b)
When two things combine and EXPLODE.
8.
Which is the name of the kind of solid substance formed in this figure?
a)
aqueous
b)
precipitate
c)
acid
d)
synthesis
9.
Which of the following examples shows that a chemical reaction has occurred?
a)
A rock breaks into smaller pieces when it is struck with a hammer.
b)
Rust forms on a hammer that has been left outside to long.
c)
A cup of water turns pink when a few drops of red food coloring are added.
d)
A solid is formed when heat is removed from a sample of water.
10.
Which of the following is NOT evidence that that a chemical reaction has occurred?
a)
produces light/heat
b)
production of a gas
c)
formation of a precipitate
d)
melting
11.
Which of the following equations demonstrates an actual chemical reaction that forms a new substance?
a)
A
b)
B
c)
C
d)
D
12.
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
13.
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?
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
14.
How many atoms in all are in a molecule of serotonin?
C10H12N2O
a)
22
b)
24
c)
25
d)
4
15.
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
16.
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
17.
A student places a piece of a potato into a container of hydrogen peroxide. One observation the student makes is that bubbles form around the potato. The presence of bubbles might indicate the formation of a new substance because bubbles -
a)
could show that a gas is forming
b)
always rise to the top of a liquid.
c)
are almost always perfectly spherical.
d)
usually burst after a few minutes.
18.
Four students performed four different investigations by combining different substances. Their results are shown in the table provided. In which experiment are new substances being formed?
a)
Experiment 1
b)
Experiment 2
c)
Experiment 3
d)
Experiment 4
19.
Evidence of a chemical reactions is anything that shows -
a)
a new substance has formed
b)
a solid dissolved in a liquid
c)
interaction between 2 gases
d)
a change in the state of matter
20.
In a ___________change, a substance changes into a different substance.
a)
Physical
b)
Chemical
21.
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
22.
A substance that is formed as the result of a chemical reaction is a __________________
a)
Product
b)
Reactant
c)
Starters
d)
Enders
100 %
