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Worksheets8.5DE - Chemical Reactions & Formulas
Total questions: 58
Worksheet time: 2hrs 56mins
Name
Class
Date
1.
Which of the following describes a precipitate?
a)
a liquid forms when a block of metal is heated
b)
a solid forms when one liquid is poured into another
c)
a gas forms when a solid is placed in a liquid
d)
bubbles form when an acid is poured on a rock
2.
Which is NOT an indication of a chemical change?
a)
temperature change
b)
formation of a precipitate
c)
shape change
d)
production of light
3.
What is the right part of a chemical equation called?
H2 + O → H2O
H2 + O → H2O
a)
Reactants
b)
Products
c)
Yields
d)
Chemical Equation
4.
The Law of Conservation of Mass states that -
a)
the number and type of atoms on both sides of a chemical reaction are equal
b)
there are more atoms on the reactant side than the product side
c)
there are more atoms on the product side than the reactant side
d)
the mass of the product will not equal the reactants
5.
You know you a chemical reaction has occurred if:
a)
there is a precipitate.
b)
there is a permanent color change.
c)
there is a temperature change.
d)
All of these answers are evidence.
6.
In the equation,
2Mg + O2 ---> 2MgO, which are the reactants?
a)
2Mg + O2
b)
2MgO
c)
2Mg and MgO
d)
O2 and MgO
7.
At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?
a)
the product is doubled
b)
the product is half the mass of the reactants
c)
the mass is the same
d)
the mass changes depending on the reaction
8.
Which of the following is a sign that a chemical reaction has occurred?
a)
change in shape
b)
melting
c)
formation of a gas
d)
dissolving
9.
Is hammering wood together to build a house a chemical or physical change?
a)
chemical
b)
physical
10.
Is melting butter for popcorn a chemical or physical change?
a)
chemical
b)
physical
11.
Is bleaching your hair a physical or chemical change?
a)
physical
b)
chemical
12.
Is burning wood a chemical or physical change?
a)
chemical
b)
physical
13.
Photosynthesis is an example of a:
a)
physical change
b)
chemical change
14.
What is the definition of chemical change?
a)
any change that results in the formation of new chemical substances.
b)
changing clothes
c)
matter cannot be created or destroyed, only change form
d)
changes affecting the form of a chemical substance, but not its chemical composition.
15.
What is the definition of physical change?
a)
any change that results in the formation of new chemical substances.
b)
rusting
c)
changes affecting the form of a chemical substance, but not its chemical composition.
d)
any property that is measurable, whose value describes a state of a physical system
16.
Marie had a beaker with a small amount of baking soda. She added a few drops of pickle juice to the baking soda and observed fizzing and bubbling. Based on her observation, which of these can Marie determine about the new substance formed by mixing the baking soda and pickle juice?
a)
A chemical reaction produced a solid.
b)
A chemical reaction produced a gas.
c)
No chemical reaction took place.
d)
Only a physical change happened.
17.
The Best Friend's Club uses "invisible ink" to write notes to each other. The invisible ink is actually lemon juice that is clear when it dries on paper, but turns brown when a club member holds a burning candle under the paper. Once it is heated, it is never invisible again.
What type of change is occurring when the paper is heated?
What type of change is occurring when the paper is heated?
a)
chemical change
b)
elemental change
c)
physical change
d)
temperature change
18.
A substance is added to a liquid. Which of the following would provide evidence to suggest a chemical change has taken place?
a)
The liquid gives off heat.
b)
The granules dissolve completely.
c)
The volume of the liquid increases.
d)
The granules seem to get smaller.
19.
A student mixes two clear liquids together. After a few minutes, a white powdery solid can be seen settling on the bottom of the test tube. Which of the following is a conclusion that the student can draw based on these observations? The two clear liquids –
a)
were pure substances before they were mixed.
b)
are toxic and should be handled with extreme caution.
c)
have gone through a chemical change in which a new substance called a precipitate was produced.
d)
have been stored too long and are no longer good.
20.
A scientist places 10 ml of water in a test tube and heat it over a Bunsen burner for 2 minutes. The liquid boils and escapes as a steam. This experiment is a good example of a
a)
chemical change
b)
physical change
c)
chemical propeety
d)
physical property
21.
An gel ice pack getting cold after you put it in the freezer for an hour.
a)
Chemical Change
b)
Physical Change
22.
A copper penny turning greenish after a few years.
a)
Chemical Change
b)
Physical Change
23.
Green bananas turning yellow on their own as they ripen.
a)
Chemical Change
b)
Physical Change
24.
A change in which NEW substances are formed.
a)
Chemical change
b)
Physical change
c)
Casual change
d)
Formal change
25.
Which of the following is NOT an example of chemical change?
a)
sour milk
b)
burning wood
c)
breaking a pencil
d)
rust
26.
Is mold growing on cheese a physical or chemical change?
a)
Physical
b)
Chemical
27.
Is Gatorade powder dissolving in water physical or chemical change?
a)
Physical
b)
Chemical
28.
A substance that undergoes a(n) _____ change becomes a new kind of substance.
a)
Chemical
b)
Physical
29.
How many atoms are in C6H12O6?
a)
12
b)
26
c)
24
d)
14
30.
How many atoms of carbon (C) are in C6H12O6?
a)
3
b)
6
c)
12
d)
24
31.
The red numbers in the image below represent ________
a)
subscripts
b)
coefficients
c)
I don't know, and don't want to try
d)
None of the answers are correct
32.
Is this equation balanced?
a)
yes
b)
no
c)
Not enough information
33.
Is this equation balanced?
a)
yes
b)
no
c)
Not enough information
34.
What does the Law of Conservation of Mass state?
a)
Matter cannot be gained or lost in a chemical reaction.
b)
Matter can only be lost in a chemical reaction.
c)
Matter can only be gained in a chemical reaction.
d)
Matter can be gained and lost in a chemical reaction.
35.
KMnO4
How many total atoms are in this compound?
How many total atoms are in this compound?
a)
1
b)
3
c)
6
d)
8
36.
What will have more mass when a chemical change is complete? The reactants before the chemical reaction, or the product after the reaction is complete?
a)
They both will have the same mass
b)
The product always has more mass than the reactant
c)
The reactant will have more mass than the product
d)
They both will loose mass after the reaction
37.
If reaction starts with 20g of reactants it should produce
a)
a total of 40g of products
b)
a total of 10g of products
c)
a total of 80 g of products
d)
a total of 20g of products
38.
A chemical reaction is balanced when:
a)
both sides have the same elements
b)
both sides have the same number and type of atoms
c)
both sides have the same subscripts
d)
both sides have the same coefficients
39.
Matter can not be created nor destroyed, it can only be
a)
Destroyed a little bit
b)
Invisible
c)
Transformed, changed
d)
None of the above
40.
How many atoms of Oxygen are in Al₂(SO₄)₃?
a)
4
b)
12
c)
7
d)
24
41.
What is the arrow in a chemical equation...
H2 + O --> H2O
H2 + O --> H2O
a)
Reactants
b)
Products
c)
Yields
d)
Chemical Equation
42.
A chemical equation tells us:
a)
the reactants and the products.
b)
the elements that make up the reactants and the products.
c)
the number of atoms that make up the reactants and the products.
d)
All of the above.
43.
What will happen to the mass of the product if I double the mass of the reactants?
a)
It will decrease by half.
b)
It will increase by half.
c)
It will double.
d)
The mass remains the same.
44.
How many Calcium atoms are in this compound?
Ca (OH)2
Ca (OH)2
a)
2
b)
3
c)
1
d)
4
45.
How many atoms of aluminum are on each side of the following equation?
4Al + 3O2 --> 2Al2 O3
4Al + 3O2 --> 2Al2 O3
a)
2
b)
6
c)
1
d)
4
46.
Is this equation balanced?...
Al + O2 --> 2Al2O3
Al + O2 --> 2Al2O3
a)
Yes
b)
No
47.
Does this equation obey the Law of Conservation of Mass?
CS2 + 202 --> CO2 +2SO2
a)
Yes
b)
No
48.
Which equation is balanced?
a)
PbO2 + 2H2
b)
SO2 + H2O --> H2SO4
c)
2Na + 2H2O --> 2NaOH + H2
49.
Which of the following reactions is balanced?
a)
2CH4 + O2 -> CO2 + H2O
b)
CH4 + 2O2 -> CO2 + H2O
c)
CH4 + 2O2 -> CO2 + 2H2O
d)
None of the chemical equations are balanced.
50.
Is this equation balanced?
2H2O + O2 --> 4MgO + 3Fe
2H2O + O2 --> 4MgO + 3Fe
a)
Yes
b)
No
51.
Is this balanced?...
Al + O2 --> 2Al2O3
Al + O2 --> 2Al2O3
a)
Yes
b)
No
52.
Which equation is balanced?
a)
3P4+ O2 ---> 2P2O3
b)
P4+ O2 ---> 2P2O3
c)
P4+ 3O2 ---> 2P2O3
d)
P4+ 2O2 ---> 3P2O3
53.
Which equation is balanced?
a)
Na3PO4 + 3KOH ---> 3NaOH + K3PO4
b)
2Na3PO4 + 2KOH ---> 3NaOH + K3PO4
c)
Na3PO4 + 2KOH ---> 2NaOH + K3PO4
d)
3Na3PO4 + 3KOH ---> 3NaOH + K3PO4
54.
Which equation is balanced?
a)
BaS + PtF2 ---> BaF2 + PtS
b)
4BaS + 2PtF2 ---> BaF2 + PtS
c)
BaS + 2PtF2 ---> 2BaF2 + 2PtS
d)
BaS + 3PtF2 ---> BaF2 + 2PtS
55.
For a chemical equation to be an example of the Law of Conservation of Mass, it must be:
a)
Complex
b)
Balanced
c)
Unbalanced
d)
Reciprocal
56.
What is a precipitate?
a)
A solid that forms as a result of a physical change
b)
A solid that forms as a result of a chemical change
57.
How many molecules of hydrogen peroxide are represented in this formula?
3H₂O₂
a)
1
b)
2
c)
3
d)
6
58.
Subscripts tell us the number of _________ of an element and coefficients tell us the number of __________ of a substance.
a)
molecules ; atoms
b)
reactants ; products
c)
atoms ; molecules
d)
products ; reactants
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