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8.6BE Law of Conservation of Mass

Total questions: 150

Worksheet time: 3hrs 28mins

Name
Class
Date
1.
How many Hydrogen are in 4H2O?
a)
6
b)
8
c)
2
d)
4
2.
How many Oxygen are in H2O?
a)
1
b)
2
c)
0
d)
4
3.
How many Magnesium are in 10MgCl2?
a)
10
b)
5
c)
20
4.
How many O's are in Al₂(SO₄)₃
a)
4
b)
12
c)
7
d)
24
5.
Number of H in 3(NH₄)₂CrO₄
a)
4
b)
2
c)
8
d)
24
6.
How many atoms are there TOTAL in:
H2SO4
a)
6
b)
5
c)
7
d)
3
7.
How many elements are in C6H12O6?
a)
1
b)
2
c)
3
d)
4
8.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
9.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
10.
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
11.
How many O's are in Al₂(SO₄)₃
a)
4
b)
12
c)
7
d)
24
12.

What elements are represented in this chemical formula? Fe2O3Fe_2O_3  

a)

Iron, Oxygen

b)

Francium, Europium, Oxygen

c)

Ferrium, Oxygen

d)

Berylium, Oxygen

13.

What is the total number of atoms in this formula? H2O2H_2O_2  

a)

2

b)

4

c)

3

14.

How many more atoms of Oxygen than than Magnesium are in this formula? (subtraction) MgSO4MgSO_4  

a)

4

b)

3

c)

2

d)

6

15.

Is this an element or a compound? CaSO4CaSO_4  

a)

Element

b)

Compound

16.

Which chemical formula correctly displays 1 atom of nickel and 2 atoms of Fluorine?

a)

niF2

b)

NIF2

c)

Ni1F2

d)

NiF2

17.

What is the total number of atoms in this chemical formula? C8H3NaBr12C_8H_3NaBr_{12}  

a)

18

b)

12

c)

25

d)

24

18.

2 CH2CO3OH

Number of C: ​ (a)  

Number of H: ​ (b)  

Number of O: ​ (c)  

Choose from the below words
4
6
8
2
3
1
5
7
9
10
19.

Match the element to the number of atoms it has.

2 Al(C2H3O4)2

a)

aluminum

1.

2

b)

carbon

2.

8

c)

hydrogen

3.

12

d)

oxygen

4.

16

20.

Coefficients in chemical formulas...

a)

are found at the beginning of a formula and multiply just the first atom

b)

are found at the end of a formula and multiply EVERYTHING!

c)

are found at the end of a formula and multiply only elements inside the parentheses.

d)

are found at the beginning of a formula and multiply EVERYTHING!

21.

How man atoms of carbon are there?

a)

1

b)

2

c)

3

d)

4

22.

How many atoms of Iron are in this compound?

a)

1

b)

2

c)

3

d)

4

23.

How many atoms of hydrogen are in

C6H12O6

a)

6

b)

12

c)

18

d)

2

24.

A substance made up of atoms of two or more different elements joined by chemical bonds

a)

Molecule

b)

compound

c)

polar covalent bond

d)

nonpolar covalent bond

25.

How many different elements are present in H2COCH2

a)

5

b)

4

c)

3

d)

2

26.

Calculate the number of Oxygen atoms in Al(OH)3

a)

1

b)

2

c)

3

d)

4

27.

How many total POTASSIUM atoms are in this formula?

a)

8

b)

2

c)

4

d)

12

28.

How many elements are in this chemical formula? NaHCO3NaHCO_3  

a)

1

b)

2

c)

3

d)

4

29.

Coefficients in chemical formulas...

a)

Multiply just the first atom

b)

Add to the subscripts at the end of the molecule

c)

Multiply elements without subscripts

d)

Multiply EVERYTHING!

30.

C3H5(NO3)3

a)

C = 3, H = 5, N = 3, O = 9

b)

C = 3, H = 5, N = 1, O = 9

c)

C = 9, H = 15, N = 3, O = 9

d)

C = 9, H = 15, N = 1, O = 3

31.
How many elements are in C6H12O6?
a)
1
b)
2
c)
3
d)
4
32.
Which of the following is a compound?
a)
Co
b)
O2
c)
C
d)
CO2
33.
How many atoms of carbon (C) are in C6H12O6?
a)
3
b)
6
c)
12
d)
24
34.
How many atoms of Oxygen are in Fe(NO3)3 ?
a)
6
b)
3
c)
9
d)
1
35.

Are there any compounds on the periodic table?

a)

yes there are many

b)

no because only elements are on the periodic table

c)

I think they are?

d)

there is no way to tell

36.

How many Hydrogen atoms are in 4H2O?

a)

6

b)

8

c)

2

d)

4

37.

How many Oxygen atoms are in H2O?

a)

1

b)

2

c)

0

d)

4

38.

How many Magnesium atoms are in 10MgCl2?

a)

10

b)

5

c)

20

39.

How many Sodium atoms are in 6NaCl?

a)

1

b)

12

c)

6

40.

What is C2H8O ?

a)

Element

b)

Letters

c)

Numbers

d)

Compound

41.

How many Aluminum atoms are in Al2O3?

a)

3

b)

2

c)

5

d)

1

42.

A subscript is the small number below the element symbol that tells the number of _______ of that element.

a)

atoms

b)

valence electrons

c)

protons

d)

elements

43.

How many atoms are there TOTAL in H2SO4 ?

a)

6

b)

5

c)

7

d)

3

44.

How many Nitrogen atoms are in (NH₄)₂CrO₄?

a)

1

b)

2

c)

8

d)

16

45.

How many atoms of Hydrogen are in this compound?

a)

1

b)

2

c)

3

d)

4

46.

How many Oxygen atoms are in Al₂(SO₄)₃?

a)

4

b)

12

c)

7

d)

24

47.

How many Hydrogen atoms in 3(NH₄)₂CrO₄?

a)

4

b)

2

c)

8

d)

24

48.

How many Nitrogen atoms are in the in H2C3O4N5?

a)

2

b)

3

c)

4

d)

5

49.

How many elements are present in this compound? (Careful!)

Mg2As3COHNi2

a)

2

b)

4

c)

6

d)

10

50.

How many atoms are present if there is no subscript following the element symbol?

a)

0

b)

2

c)

only 1

d)

1 million

51.

If a reaction starts with a total 54g of reactants it should produce 

a)
a total of 40g of products
b)

a total of 54g of products

c)
a total of 180 g of products
d)
None of the above
52.

O + H2 → H2O

32 g of Oxygen completely reacts with 8 g of Hydrogen to produce _____ g of water.

a)

8

b)

12

c)

24

d)

40

53.

Mg + F → MgF

24 g of magnesium reacts with 38 g of fluorine to produce _____ g magnesium fluoride.

a)
62 
b)
38
c)
24
d)
14
54.

How many elements does PbNO7 have?

Hint: Every capital letter😉

a)
2
b)
3
c)
4
d)
5
55.
How many nitrogen atoms does NH3 have?
a)
1
b)
2
c)
3
d)
4
56.

Substances present at the start of a chemical reaction are called ____.

a)
subscripts
b)
coefficients
c)
reactants
d)
products
57.

Substances that form as the result, or at the end, of a chemical reaction are called ____.

a)
products
b)
reactants
c)
coefficients
d)
subscripts
58.

How many iron (Fe) atoms are in 
Fe(NO3)2

a)
1
b)
2
c)
3
d)
6
59.

How many nitrogen (N) atoms are in 
Fe(NO3)2

a)
1
b)
2
c)
3
d)
6
60.

How many oxygen (O) atoms are in 
Fe(NO3)2

a)
1
b)
2
c)
3
d)
6
61.
Matter can not be created nor destroyed: it can only be
a)
Destroyed a little bit
b)
Invisible
c)

Transformed, rearranged

d)
None of the above
62.

Label the reactants and products of the chemical reaction shown.

a)

Reactants

b)

Products

1
2
1)
2)
63.

Label the reactants and products in the chemical equation shown.

a)

Reactants

b)

Products

1
2
1)
2)
64.

What are the reactants in this chemical equation?

a)

6 CO2 + 6 H2O

b)

H2O

c)

C6H12O6

d)

C6H12O6 + O2

65.

What are the products in this chemical equation?

a)

CO2 + H2O

b)

H2O

c)

C6H12O6

d)

C6H12O6 + O2

66.

Select the chemical formula for this molecule?

a)

B1F3

b)

BF

c)

BF3

d)

FB

67.

How many atoms of hydrogen are in

C6H12O6

a)

6

b)

12

c)

18

d)

2

68.

Examine the experiment shown, then fill in the blanks.

The experiment shows a ​ (a)   system.

The mass at the end of the experiment will be ​ (b)   the initial mass.

Choose from the below words
closed
open
equal to
less than
greater than
69.

How many grams of Zn(NO3)2 was produced?

a)

3 g

b)

4 g

c)

0 g

d)

5 g

70.

If AB is 18 grams and reacts in a closed system, which of the following could be the grams of A and B?

a)

A is 13 grams and B is 2 grams

b)

A is 18 grams and B is 5 grams

c)

A is 9 grams and B is 11 grams

d)
A is 12 grams and B is 6 grams
71.

40 grams of calcium reacts with 71 grams of chlorine to produce _______ g of calcium chloride.

a)

31

b)

101

c)

100

d)

111

72.

______ g of potassium reacts with 16 g of oxygen to produce 94 g of potassium oxide.

a)

88

b)

110

c)

50

d)

78

73.

14 g of lithium reacts with _____ g of sulfur to produce 46 g of lithium sulfide.

a)

32

b)

60

c)

25

d)

10

74.

24 g of magnesium reacts with 38 g of fluorine to produce ______ g of magnesium fluoride.

a)

10

b)

24

c)

14

d)

62

75.

88 g of strontium reacts with 160 g of bromine to produce _______ g of strontium bromide.

a)

72

b)

240

c)

248

d)

80

76.

______ g of hydrogen reacts with 32 g of oxygen to produce 34 g of hydrogen peroxide.

a)

2

b)

3

c)

66

d)

64

77.

Is the chemical equation following the Law of Conservation of Mass?

3 H2 + N2 → 2 NH3

a)

Yes, it is following the Law

b)

No, it is not following the Law

78.

Is the chemical equation following the Law of Conservation of Mass?

Na2O + 2 CO2 → 2 Na2CO3

a)

Yes, it is following the Law

b)

No, it is not following the Law

79.

How many atoms in TOTAL make up the chemical equation below?

6 CO2 + 6 H2O → C6H12O6 + 6 O2

a)

18 atoms total

b)

72 atoms total

c)

36 atoms total

d)

12 atoms total

80.

How many oxygen atoms in TOTAL make up the chemical equation below?

6 CO2 + 6 H2O → C6H12O6 + 6 O2

a)

18 atoms total

b)

6 atoms total

c)

36 atoms total

d)

2 atoms total

81.

In the chemical formula C12H22O11C_{12}H_{22}O_{11}  , how many elements are there?

a)

1

b)

2

c)

3

d)

4

82.

In the chemical formula C12H22O11C_{12}H_{22}O_{11}  , how many C atoms are there?

a)

12

b)

22

c)

11

d)

45

83.

In the chemical formula C12H22O11C_{12}H_{22}O_{11}  , how many O atoms are there?

a)

12

b)

22

c)

11

d)

45

84.

In the chemical formula C12H22O11C_{12}H_{22}O_{11}  , how many H atoms are there?

a)

12

b)

22

c)

11

d)

45

85.

What is the TOTAL number of atoms in the chemical formula C12H22O11C_{12}H_{22}O_{11}  ?

a)

12

b)

22

c)

11

d)

45

86.

Which of the following substances CANNOT be broken down into simpler substance? ?

a)

NaNa  

b)

H2OH_2O  

c)

C6H12O6C_6H_{12}O_6  

d)

COCO  

87.

How does a balanced chemical equation satisfy the Law of Conservation of Mass?

a)

During a chemical reaction, matter is destroyed.

b)

During a chemical reaction, the total number of atoms increases.

c)

 During a chemical reaction, one or more new substances are formed.

d)

During a chemical reaction, the total amount of matter stays the same.

88.

What happens to the total mass of the substances after a chemical reaction?

a)

It decreases.

b)

It increases.

c)

 It remains the same.

d)

It increases then decreases.

89.

In a chemical reaction, the number of atoms in the products will always equal which amount?

a)

the number of atoms in the reactants

b)

half of the number of atoms in the reactants

c)

twice the number of the atoms in the reactants

d)

thrice the number of the atoms in the reactants

90.

Jin bought a heat pack that weighs 15 g. He shook it so it would release heat to warm his hands. The release of heat indicates a chemical reaction took place in a closed system. What would be the mass of the heat pack after the chemical reaction?

a)

5 g

b)

10 g

c)

12 g

d)

15 g

91.

The chemical formula for baking soda is NaHCO3NaHCO_3   . How many O atoms does it have?

a)

1

b)

2

c)

3

d)

4

92.
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
93.
The number to the lower side of an element is a 
a)
Subscript
b)
Superscript
c)
Coefficient
d)
Charge
94.
The number in front of a compound or element is a 
a)
Subscript
b)
Coefficient
c)
Superscript
d)
Charge
95.
A chemical reaction is balanced when
a)
both sides have the same elements
b)
Both sides have the same  number of atoms
c)
Same subscripts
d)
Same coefficients
96.
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
97.
What is the Law of Conservation of mass?
a)
Mass is created in a chemical reaction
b)
Mass is created in a physical change
c)
New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
d)
Mass is never created or destroyed
98.
Maria fills a bowl with 200 g of water. She puts the bowl of water in the freezer, and the water freezes. Which will most likely be the mass of the frozen water?
a)
50 g
b)
100 g
c)
200 g
d)
400 g
99.

How many atoms do you have in the compound 2MgCl2?

a)

2 atoms

b)

4 atoms

c)

6 atoms

d)

8 atoms

100.

How many Ca (Calcium) atoms are found in Ca(OH)2?

a)

5 atoms

b)

3 atoms

c)

2 atoms

d)

1 atom

101.
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
102.
The number to the lower side of an element is a 
a)
Subscript
b)
Superscript
c)
Coefficient
d)
Charge
103.
The number in front of a compound or element is a 
a)
Subscript
b)
Coefficient
c)
Superscript
d)
Charge
104.
A chemical reaction is balanced when
a)
both sides have the same elements
b)
Both sides have the same  number of atoms
c)
Same subscripts
d)
Same coefficients
105.
In a synthesis reaction
a)
A compound breaks apart into two or more compounds
b)
Two or more compounds make one single product
c)
CO2 and H2O must be products
d)
O2 must be a reactant
106.
Which of these is not a chemical reaction?
a)
Burning of wood
b)
Milk going bad
c)
Mixing vinegar and baking soda
d)
Melting of ice
107.
The coefficient in  3H2O is
a)
6
b)
2
c)
3
d)
5
108.
A precipitate is a 
a)
liquid that forms when two solids are reacted
b)
a solid that forms when two liquids are mixed
c)
a gas that forms when vinegar and baking soda react
d)
a change of color in a solution
109.
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
110.
In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 
a)
4g
b)
5g
c)
9g
d)
14g
111.
What will weigh more when a chemical change is complete?  The reactants before the chemical reaction, or the product after the reaction is complete?
a)
They both will weigh the same
b)
The product always weighs more than the reactant
c)
The reactant will weigh more than the product
d)
They both will loose mass after the reaction
112.
What types of systems are there?
a)
Mechanical and Electrical Systems
b)
Inside and Outside Systems
c)
Open and Closed Systems
d)
Human and Machine Systems
113.
This type of system allows matter to flow freely in and out...
a)
Closed System
b)
Open System
114.
A boiling pot with a lid on it to keep in the energy is what type of system?
a)
Closed System
b)
Open System
115.
Measure of the amount of matter 
a)
mass
b)
volume
c)
weight
d)
density
116.
What is the Law of Conservation of mass?
a)
Mass is created in a chemical reaction
b)
Mass is created in a physical change
c)
New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
d)
Mass is never created or destroyed
117.
Since gasses weigh nothing, when they are produced in a reaction they do not have to be accounted for.  
a)
True
b)
False
118.
O3 ---> O + O2
a)
Synthesis
b)
Single Replacement
c)
Decomposition 
d)
Combustion
119.
P4 + 3 O2 ---> 2 P2O3
a)
Single Replacement
b)
Combustion
c)
Synthesis
d)
Decomposition
120.
Which are the reactants in the following reaction?
2Mg + O2 ---> 2MgO 
a)
Mg and O
b)
MgO
c)
Mg and MgO
d)
O and MgO
121.

How many atoms do you have in the compound 2MgCl2?

a)

2 atoms

b)

4 atoms

c)

6 atoms

d)

8 atoms

122.

How many Ca (Calcium) atoms are found in Ca(OH)2?

a)

5 atoms

b)

3 atoms

c)

2 atoms

d)

1 atom

123.

How many atoms do you have in the chemical formula 3H2O2?

a)

7 atoms

b)

12 atoms

c)

4 atoms

d)

6 atoms

124.

How many atoms do you have in the chemical formula 2Mg(ClO3)2?

a)

2 atoms

b)

7 atoms

c)

9 atoms

d)

18 atoms

125.

Law of conservation of mass states the amounts of atoms in the reactants and the products...

a)

Increase

b)

Decrease

c)

Stay the same

d)

No correct answer

126.

Does the equation H2+O2 →H2O follow the Law of Conservation of Mass?

a)

Yes, because the atoms are equal.

b)

No, because more info is needed.

c)

No, because there are more atoms in the product.

d)

No, because there are more atoms in the reactant.

127.

The Law of Conservation of Mass means that...

a)

The Mass of the reactants & products are equal.

b)

The Atoms of the reactants & products are equal.

c)

No mass or atoms is gained or lost during a chemical reaction.

d)

All the states are correct.

128.

In this reaction, how much CO2 is produced?

a)

42 g

b)

24 g

c)

23 g

d)

No grams produced

129.

In this reaction, how much O2 is produced?

a)

12 g

b)

22 g

c)

42 g

d)

No grams are produced

130.

In a reaction A + B → C, reactant A has 5 g and product C has 9 g. How many grams does reactant B should have?

a)

4 g

b)

5 g

c)

9 g

d)

14 g

131.

Does this equation follow the Law of Conservation of Mass?

2Fe2O3 + 3C → 4Fe + 3 CO2

a)

No, because there are more reactants than products.

b)

No, because there are more products than reactants.

c)

Yes, because the reactants equal the products.

d)

Yes, because the reactants do not equal the products.

132.

If a reaction starts with a total 75 g of reactants it should produce

a)

a total of 40 g of products

b)

a total of 75 g of products

c)

a total of 180 g of products

d)

No correct answer

133.

If there are 4 Hydrogen atoms on the reactant side, how many Hydrogen atoms will be on the product side?

a)

More information is needed to answer

b)

6 atoms

c)

4 atoms

d)

2 atoms

134.

What is the part of the chemical equation in green called?

Fe + S → FeS

a)

Reactants

b)

Products

c)

Yield

d)

Chemical equation

135.

What is the right part of a chemical equation called...

2H2 + O2 → 2H2O

a)

Reactants

b)

Products

c)

Yield

d)

Chemical Equation

136.

A student mixes 125 grams of sugar, 250 grams of water and 5 grams of flavoring. The solution weighs...

a)

250 grams

b)

380 grams

c)

375 grams

d)

400 grams

137.
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
138.
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
139.
What will weigh more when a chemical change is complete?  The reactants before the chemical reaction, or the product after the reaction is complete?
a)
They both will weigh the same
b)
The product always weighs more than the reactant
c)
The reactant will weigh more than the product
d)
They both will loose mass after the reaction
140.

What do we call the chemicals that result from a chemical reaction?

a)

reactants

b)

products

c)

subscripts

d)

coefficients

141.

________ are the starting substances in a chemical equation.

a)

Reactants

b)

Producer

c)

Reaction

d)

Products

142.

The law of conservation of mass states that ________

a)

the total mass of reactants is more than the total mass of products

b)

the mass of a chemical reaction is not constant

c)

the mass of a chemical reaction remains constant

d)

the total mass of reactants is less than the total mass of products

143.

Copper (Cu) and sulfur (S) were heated in a covered container. After the reaction was complete, the unreacted sulfur was removed. The table contains the results of the investigation. How much sulfur in grams failed to react with the copper?

a)

1.32 g

b)

4.54 g

c)

5.02 g

d)

10.88 g

144.

How many of each substance are present after the coefficient has been added in 3Pb(SO4)2

a)

3 Pb and 3 SO4

b)

3 Pb and 6 SO4

c)

6 Pb and 24 SO4

d)

6 Pb and 6 SO4

145.

Which of the following equations is balanced?

a)

Equation (a)

b)

Equation (b)

c)

Equation (c)

d)

Equation (d)

146.
Is this equation balanced or unbalanced?
CH4 + 2O2--> CO2+ 2H2O
a)
balanced
b)
unbalanced
147.
Is this equation balanced or unbalanced? 
2Fe2O3 + 3C --> 4Fe + 3 CO2
a)
balanced
b)
unbalanced
148.
In the reaction shown by the equation, 252 grams of FeCl2 and 70 grams of Cl2 are consumed.
2FeCl2+ Cl2--> 2FeCl3 
How many grams of FeCl3 are produced? 
a)
161 grams
b)
182 grams
c)
322 grams
d)
392 grams
149.
Which equation best represents the law of conservation of mass? 
a)
A
b)
B
c)
C
d)
D
150.

The Coefficient (3) in the Chemical Formula, 3H2O, tells you how many _____________ there are.

a)

Atoms of Hydrogen

b)

Atoms of Oxygen

c)

Atoms of Water

d)

Molecules of Water

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