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Law of Conservation of Mass, Formulas, and Bohr Models Review

Total questions: 65

Worksheet time: 1hrs 18mins

Name
Class
Date
1.

Mass is neither created nor ______________.

a)

made

b)

destroyed

c)

changed

2.

True or False: The mass of the reactants is equal to the mass of the products?

a)

True

b)

False

3.

Which of the models of a chemical reaction best represents the Law of Conservation of Mass?

a)

A

b)

B

c)

C

d)

D

4.

Which of the models of a chemical reaction best represents the Law of Conservation of Mass?

a)

A

b)

B

c)

C

d)

D

5.
The number in front of a compound or element is a 
a)
Subscript
b)
Coefficient
c)
Superscript
d)
Charge
6.
The number to the lower side of an element is a 
a)
Subscript
b)
Superscript
c)
Coefficient
d)
Charge
7.
The coefficient in  3H2O is
a)
6
b)
2
c)
3
d)
5
8.
How many nitrogen atoms does NH3 have?
a)
1
b)
2
c)
3
d)
4
9.

Which Chemical Equation is Balanced?

a)

CH₄+O₂------CO₂+2H₂O

b)

H₂+O₂-----2H₂O₄

c)

4Al+3O₂-----2Al₂O₃

10.

How many oxygen atoms are in this chemical formula?

a)

6 oxygen atoms

b)

2 oxygen atoms

c)

3 oxygen atoms

d)

4 oxygen atoms

11.

Which Chemical Equation is Balanced?

a)

Fe4+O2------4FeO2+O2

b)

2H2+O2-----2H2O

c)

3Cr+4O₂-----2Cr₂O₃

12.

Which Chemical Equation is Balanced?

a)

4O2 + 2H2 + S2------ 2H2SO4

b)

4H2+O2-----2H2O2

c)

3Cr+4O₂-----2Cr₂O₃

13.

How many Sulfur atoms are present in the reactants of the following equation: 2SO2 + 2H2O2 ----> 2H2SO4

a)

2

b)

3

c)

4

d)

8

14.

How many Hydrogen atoms are present in the product of the following equation: 2SO2 + 2H2O2 ----> 2H2SO4

a)

2

b)

3

c)

4

d)

8

15.
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
16.
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
17.
Is this equation balanced or unbalanced? 
2Fe2O3 + 3C --> 4Fe + 3 CO2
a)
balanced
b)
unbalanced
18.
Which is Chemical Equation is Balanced?
a)
CH₄+O₂------CO₂+2H₂O
b)
H₂+O₂-----2H₂O₄
c)
4Al+3O₂-----2Al₂O₃
19.
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
20.
What is the arrow in a chemical equation...
H2 + O --> H2O
a)
Reactants
b)
Products 
c)
Yields 
d)
Chemical Equation 
21.
How many elements does PbNO3 have?
a)
2
b)
3
c)
4
d)
5
22.

________ are the starting substances in a chemical equation.

a)

Reactants

b)

Producer

c)

Reaction

d)

Products

23.

Is this an example of a Physical or Chemical change? 

a)

Physical

b)

Chemical

24.

Is this a image a physical or chemical change?

a)

Physical 

b)

Chemical

25.

Is this image a physical or chemical change? 

a)

Physical 

b)

Chemical

26.

Using the picture, what is the coefficient of this chemical compound? 

a)

3

b)

4

c)

There isn't one 

27.

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

a)

12

b)

22

c)

11

d)

45

28.

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

a)

12

b)

22

c)

11

d)

45

29.

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

a)

12

b)

22

c)

11

d)

45

30.

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

31.

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  

32.

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

a)

2 atoms

b)

4 atoms

c)

6 atoms

d)

8 atoms

33.

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

a)

5 atoms

b)

3 atoms

c)

2 atoms

d)

1 atom

34.
Which of these is a chemical reaction?
a)
Boiling water
b)
Melting aluminum
c)
Crushing a piece of chalk
d)
Cooking an egg
35.
Physical properties are
a)
properties that can be observed without changing the identity of the substance
b)
properties that describe how a substance changes into a completely different substance
36.

Identify the Reactants in this equation.

a)

A

b)

B

37.
How many Sodium (Na) are in 6NaCl?
a)
1
b)
12
c)
6
38.

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

39.

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.

40.

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

2H2 + O2 → 2H2O

a)

Reactants

b)

Products

c)

Yield

d)

Chemical Equation

41.

What is a valence electron?

a)

Electrons in the first energy shell

b)

Electrons in the second energy shell

c)

Electrons in the outer shell

d)

Total number of electrons

42.

What does the Bohr Model represent?

a)

The structure of molecules

b)

The structure of the Solar System

c)

The structure of an atom

d)

The structure of East Hills

43.

Which element is this?

a)

Nickel

b)

Neon

c)

Sodium

d)

Nitrogen

44.

Name this element.

a)

Argon

b)

Chlorine

c)

Aluminum

d)

Boron

45.

Name this element.

a)

Neon

b)

Magnesium

c)

Sodium

d)

Manganese

46.

What is the atomic number of this atom?

a)

2

b)

4

c)

6

d)

8

47.

What is the mass number of this atom?

a)

1

b)

3

c)

4

d)

7

48.

What is this element?

a)

Beryllium (atomic #4)

b)

Boron (atomic #5)

c)

Carbon (atomic #6)

d)

Nitrogen (atomic #7)

49.

How many valence electrons?

a)

2

b)

3

c)

4

d)

5

50.

How many valence electrons?

a)

2

b)

3

c)

4

d)

5

51.

How many valence electrons?

a)

2

b)

4

c)

6

d)

8

52.

What group does this element belong to?

a)

1

b)

2

c)

17

d)

18

53.

How many valence electrons?

a)

2

b)

5

c)

6

d)

8

54.

What element is represented in this Bohr Model?

a)

Carbon

b)

Hydrogen

c)

Aluminum

d)

Lithium

55.

Which element does this Bohr model represent?

a)

Aluminum

b)

Silicon

c)

Magnesium

d)

Cobalt

56.

What is the mass of this atom?

a)

9

b)

10

c)

19

d)

28

57.

Which Element is this?

a)

Carbon (C)

b)

Fluorine (F)

c)

Boron (B)

d)

Sodium (Na)

58.

Which Element is this?

a)

Neon (Ne)

b)

Calcium (Ca)

c)

Potassium (K)

d)

Zirconium (Zr)

59.

How many energy levels do elements in period 4 have?

a)

2

b)

3

c)

4

d)

5

60.

How many electrons in the outer energy level are in elements in group 13, 3A?

a)

13

b)

14

c)

6

d)

3

61.

What does the period number tell you about an element?

a)

Number of energy levels

b)

Number of valence electrons

62.

What does the group number tell you about an element?

a)

The number of energy levels

b)

The number of valence electrons

63.

What is wrong with this model?

a)

The electrons are the same as the protons and neutrons

b)

The neutrons are too large

c)

The protons and neutrons should be smaller than the electrons

d)

There is nothing wrong with this model

64.

Which of the following models is the best representation of a Bohr model?

a)

A

b)

B

c)

C

65.

Which one is the correct Bohr model for Sodium?

a)

A

b)

B

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