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WorksheetsChemical Reactions, Equations, Balancing of Equations
Total questions: 20
Worksheet time: 12mins
Name
Class
Date
1.
Is the following equation balanced or unbalanced?
Fe + S --> FeS
Fe + S --> FeS
a)
balanced
b)
unbalanced
2.
True or False: When balancing chemical equations the subscripts can change.
a)
true
b)
false
3.
Which of the Following Correctly Balances this Equation?
_H2+_Cl2 --> _HCl
_H2+_Cl2 --> _HCl
a)
2H2 + Cl2 --> 4HCl
b)
H2+Cl2 --> 2HCl
c)
3H2 + 3Cl2 --> HCl
d)
H + Cl --> HCl
4.
When balancing equations a ____ can be placed to the left of a formula of a substance to make the equations balanced
a)
charge
b)
subscript
c)
random number
d)
coefficient
5.
When balancing equations what does
-->
mean?
-->
mean?
a)
subscript
b)
equals
c)
it is just an arrow
d)
yield
6.
Classify the following chemical reaction:
4P +5O2 --> P4O10
4P +5O2 --> P4O10
a)
single replacement
b)
double replacement
c)
synthesis
d)
decomposition
7.
Which of the following is an unbalanced equation?
a)
CaCO3 --> CaO + CO2
b)
PbO2 + 2H2-->2Pb + H2O
c)
2Na+ 2H2O-->2NaOH + H2
d)
CS2 + 2O2 --> CO2 + 2SO2
8.
Which of the following is an example of synthesis?
a)
Na + Br2 --> NaBr
b)
KClO3 --> KCl + O2
c)
HgO + Cl2-->HgCl + O2
d)
Cl2 + NaBr --> NaCl + Br2
9.
Which of the following is evidence of a chemical reaction?
a)
fizzing
b)
water changing to ice
c)
saltwater
d)
paper being cut in half
10.
What coefficient should be used to make the following equation balanced?
N2+O2--> _NO
N2+O2--> _NO
a)
1
b)
2
c)
3
d)
4
11.
When a chemical reaction is classified as decomposition what happens in the experiment?
a)
The elements are combined to create one chemical formula.
b)
The elements break down
c)
The elements replace each other
12.
What is a chemical equation?
a)
A short way to show a chemical reaction using symbols
b)
A way to explain a chemical reaction using words
13.
True or False: Chemical equations use symbols instead of words to summarize chemical reactions.
a)
false
b)
true
14.
The substances at the beginning of a chemical reaction are called the ____
a)
product
b)
yield
c)
chemical symbol
d)
reactants
15.
What is the part of the chemical equation in green called?
Fe + S --> FeS
Fe + S --> FeS
a)
products
b)
reactants
c)
yield
d)
chemical formula
16.
True or False: Chemical equations have no real structure.
a)
true
b)
false
17.
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
18.
How many atoms of aluminum are on each side of the following equation: 4Al + 3O2 --> 2Al2 O3
a)
2
b)
6
c)
1
d)
4
19.
Why is the following chemical equation not balanced?
H2 + O2 --> H2O
H2 + O2 --> H2O
a)
each side of the equation has a different number of oxygen atoms
b)
each side of the equation has a different number of hydrogen atoms
c)
each side has the same mass
20.
What category does the following equation belong in?
Cl2 + NaBr --> NaCl + Br2
Cl2 + NaBr --> NaCl + Br2
a)
double replacement
b)
single replacement
c)
decomposition
d)
synthesis
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