WorksheetsChemical Equations and counting atoms
Total questions: 95
Worksheet time: 2hrs 33mins
Name
Class
Date
1.
Which of the following is evidence that a chemical change has taken place?
a)
change in color
b)
change in size
c)
change in shape
d)
change in energy
2.
When dry ice (solid carbon dioxide) sublimes it goes directly from a solid to a gas. What type of change is occurring?
a)
Chemical change
b)
Physical change
c)
None of the above
3.
How many oxygen atoms are present in the following?
4Ca(OH)2
4Ca(OH)2
a)
4
b)
6
c)
8
d)
1
4.
Why must we balance chemical equations?
a)
Our teacher said so
b)
to abide by the law of conservation of energy
c)
to abide by the law of conservation of mass
5.
What is changed in a chemical reaction like this one?
NaOH + HCl → NaCl + H2O
NaOH + HCl → NaCl + H2O
a)
the number of atoms is changed
b)
molecules and compounds are changed
c)
atoms are changed
d)
elements are changed
6.
Which of the following can be broken apart in a chemical reaction?
a)
Noble gases
b)
Molecules and compounds
c)
only molecules
d)
only compounds
7.
How many atoms of carbon (C) are in C6H12O6?
a)
3
b)
6
c)
12
d)
24
8.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
9.
How many Aluminum are in Al2O3?
a)
3
b)
2
c)
5
10.
How many Hydrogen are in 4H2O?
a)
6
b)
8
c)
2
d)
4
11.
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.
12.
How many HCl molecules do you need to balance this equation?
Mg + __HCl ---> MgCl2 + H2
Mg + __HCl ---> MgCl2 + H2
a)
1
b)
2
c)
3
d)
4
13.
The substances listed on the right side of a chemical equation are the
a)
Yields
b)
Reactants
c)
Products
d)
Precipitates
14.
The substances listed on the left side of a chemical equation are the
a)
Products
b)
Coefficients
c)
Precipitates
d)
Reactants
15.
In chemical reactions, what does the principle of conservation of mass mean?
a)
Matter is not created or destroyed.
b)
The total mass of the reactants is greater than the total mass of the products.
c)
The total mass of the reactants is less than the total mass of the products.
d)
Matter is not changed.
16.
Which is the Law of Conservation of Matter?
a)
matter cannot be created or destroyed, it only rearranges
b)
matter can be created but it cannot be destroyed, it never rearranges
c)
matter can be destroyed but it cannot be created, it usually just rearranges
d)
matter is an unproven theory created by Hans Geiger
17.
Which one is a compound?
a)
Co
b)
Br
c)
Fe
d)
CO
18.
Which one is an element?
a)
Co
b)
CO
c)
CO2
d)
CO3-2
19.
How many elements are found in the following molecule? Mg(ClO3)2
a)
1
b)
4
c)
3
d)
5
20.
The substances listed on the right side of a chemical equation are the
a)
Yields
b)
Reactants
c)
Products
d)
Precipitates
21.
CaCO3 represents a chemical
a)
Symbol
b)
Formula
c)
Subscript
d)
Reaction
22.
The substances listed on the left side of a chemical equation are the
a)
Products
b)
Coefficients
c)
Precipitates
d)
Reactants
23.
A molecule is smaller than an atom.
a)
True
b)
False
24.
How many Oxygen (O) atoms are in 2C2HO8Cl2
a)
2
b)
16
c)
8
d)
5
25.
2H2 + O2 ----> 2H2O What is the product?
a)
------>
b)
2H2O
c)
2H2+ O2
26.
How many Magnesium are in 10MgCl2?
a)
10
b)
5
c)
20
27.
What is a coefficient?
a)
The small number on the right of the chemical symbol.
b)
The large number to the left of a formula.
28.
Is this equation balanced?
a)
yes
b)
no
c)
Not enough information
29.
How many atoms of Carbon are in the compound C2H8O ?
a)
8
b)
2
c)
1
d)
11
30.
The law of conservation of matter states that
a)
chemical reactions change matter.
b)
in chemical reactions, the identity of reactants and products is conserved.
c)
atoms are neither created nor destroyed in chemical reactions.
d)
a chemical equation must be balanced.
31.
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
32.
Is the following equation balanced or unbalanced?
Fe + S --> FeS
Fe + S --> FeS
a)
balanced
b)
unbalanced
33.
Which of the following is an unbalanced equation?
a)
CaCO3 --> CaO + CO2
b)
PbO2 + 2H2-->2Pb + H2O
c)
2Na+ 2H2O-->2NaOH + H2
d)
CS2 + 3O2 --> CO2 + 2SO2
34.
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
35.
Is this balanced?...
Al + O2 --> 2Al2O3
Al + O2 --> 2Al2O3
a)
Yes!
b)
NO!
36.
In this image, the information in red is called the_______.
a)
Products
b)
Reactants
c)
Chemical Subscript
d)
Ingredients
37.
In this image, the information to the right of the arrow (in black) is called the_______.
a)
Product
b)
Reactant
c)
Chemical Subscript
d)
Final chemical
38.
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.
39.
How many ELEMENTS are in the compound H2O
a)
1
b)
2
c)
3
d)
4
40.
How many ELEMENTS are in the compound O2
a)
1
b)
2
c)
3
d)
4
41.
How many ATOMS of Carbon are in 3C2H4O
a)
2
b)
3
c)
4
d)
6
42.
How many ATOMS of Oxygen are in 3Fe2O3
a)
2
b)
3
c)
6
d)
9
43.
How many TOTAL atoms are in 2H2SO4
a)
2
b)
4
c)
7
d)
14
44.
How many TOTAL atoms are in 2CaO2
a)
2
b)
3
c)
5
d)
6
45.
Is the following equation balanced or unbalanced ?
Al + O2 --> Al2O3
Al + O2 --> Al2O3
a)
Balanced
b)
Unbalanced
46.
Is the following equation balanced or unbalanced ?
N2 +3 H2 --> 2NH3
N2 +3 H2 --> 2NH3
a)
Balanced
b)
Unbalanced
47.
How many atoms of lead (Pb) are in Pb(NO₃)₂?
a)
1
b)
2
c)
3
d)
6
48.
How many atoms of carbon (C) are in C6H12O6?
a)
3
b)
6
c)
12
d)
24
49.
What is the left part of a chemical equation called?
2H2 + O2 --> 2H2O
2H2 + O2 --> 2H2O
a)
Reactants
b)
Products
c)
Yields
d)
Chemical Equation
50.
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.
51.
What is the right part of a chemical equation called...
2H2 + O2 --> 2H2O
2H2 + O2 --> 2H2O
a)
Reactants
b)
Products
c)
Yields
d)
Chemical Equation
52.
What is the little number after an element in a chemical equation called.
Example: H2
Example: H2
a)
Coefficient
b)
Subscript
c)
Atom
d)
Equation
53.
What is the total number of atoms present in 5Na3PO4
a)
5
b)
40
c)
55
d)
8
54.
Is the following equation balanced?...
Al + O2 --> 2Al2O3
Al + O2 --> 2Al2O3
a)
Yes!
b)
No!
55.
Which side of a chemical equation is the reactant side?
a)
Left (before the yields sign)
b)
Right (after the yields sign)
56.
Which side of a chemical equation os the product side?
a)
Left (before the yields sign)
b)
Right (after the yields sign)
57.
Which problem is balanced?
a)
PbO2 + 2H2
b)
SO2 + H20 --> H2SO4
c)
2Na + 2H2O --> 2NaOH + H2
58.
What is the little number after an element in a chemical equation called.
Example: H2
Example: H2
a)
Coefficient
b)
Subscript
c)
Atom
d)
Equation
59.
Is the equation balanced?: 2H2O + O2 --> 4MgO + 3Fe
a)
Yes
b)
No
60.
Is this equation balanced?
a)
yes
b)
no
c)
Not enough information
61.
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
62.
How many atoms are there TOTAL in:
H2SO4
H2SO4
a)
6
b)
5
c)
7
d)
3
63.
The two sides of a chemical equation are called?
a)
Reactants (left) and Products (right)
b)
Ingredients (left) and Product (right)
c)
Cations and Anions
d)
Reactants (left) and Results (right)
64.
How many atoms are there TOTAL in:
H2SO4
H2SO4
a)
6
b)
5
c)
7
d)
3
65.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
66.
How many O's are in Al₂(SO₄)₃
a)
4
b)
12
c)
7
d)
24
67.
How many Aluminum are in Al2O3?
a)
3
b)
2
c)
5
68.
Number of N in (NH₄)₂CrO₄
a)
1
b)
2
c)
8
d)
16
69.
How many Elements are in the compound C2H8O ?
a)
2
b)
1
c)
3
d)
0
70.
A subscript is the small number below a(n) ________ that tells the number of _______ of that element.
a)
element symbol; atoms
b)
atom; element symbol
c)
subscript; protons
d)
compound; elements
71.
If there is no subscript, there is ______ atom(s) of that element.
a)
0
b)
2
c)
only 1
d)
1 million
72.
How many atoms of Hydrogen are in this compound
a)
1
b)
2
c)
3
d)
4
73.
In this compound structure of alcohol, how many Hydrogen atoms are there?
a)
2
b)
4
c)
6
d)
8
74.
How many elements are present in this compound?
Mg2As3COHNi2
Mg2As3COHNi2
a)
2
b)
4
c)
6
d)
10
75.
How many Magnesium are in 10MgCl2?
a)
10
b)
5
c)
20
76.
How many total atoms are in the compound C2H8O ?
a)
11
b)
2
c)
8
d)
1
77.
How many molecules are in 10MgCl2?
a)
10
b)
5
c)
20
78.
How many molecules are in 10MgCl2?
a)
10
b)
5
c)
20
79.
How many Oxygen atoms are in H2O?
a)
1
b)
2
c)
0
d)
4
80.
How many elements are in C6H12O6?
a)
1
b)
2
c)
3
d)
4
81.
Element or compound?
O2
O2
a)
Element
b)
Compound
82.
Which of the following is a compound?
a)
Co
b)
O2
c)
C
d)
CO2
83.
Which is the correct formula for:
three hydrogen (H)
one sulfur (S)
four oxygen (O)
three hydrogen (H)
one sulfur (S)
four oxygen (O)
a)
H3SO4
b)
HSO4
c)
H4S3O
d)
H2O
84.
How many atoms are there TOTAL in:
H2SO4
H2SO4
a)
6
b)
5
c)
7
d)
3
85.
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.
86.
How many HCl molecules do you need to balance this equation?
Mg + __HCl ---> MgCl2 + H2
Mg + __HCl ---> MgCl2 + H2
a)
1
b)
2
c)
3
d)
4
87.
The substances listed on the right side of a chemical equation are the
a)
Yields
b)
Reactants
c)
Products
d)
Precipitates
88.
Which is the correct formula for:
three hydrogen (H)
one sulfur (S)
four oxygen (O)
three hydrogen (H)
one sulfur (S)
four oxygen (O)
a)
H3SO4
b)
HSO4
c)
H4S3O
d)
H2O
89.
Number of C's in 2Na₂CO₃
a)
1
b)
2
c)
3
d)
5
90.
The number of Na's in Na₂CO₃
a)
1
b)
2
c)
3
d)
6
91.
How many Elements are in the compound C2H8O ?
a)
2
b)
1
c)
3
d)
0
92.
How many total atoms are in the compound C2H8O ?
a)
11
b)
2
c)
8
d)
1
93.
How many Aluminum are in Al2O3?
a)
3
b)
2
c)
5
94.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
95.
How many Chlorine are in MgCl2?
a)
2
b)
1
c)
3
100 %
