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Chemical Reactions and Conservation of Mass

Total questions: 35

Worksheet time: 36mins

Name
Class
Date
1.

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

a)

12

b)

22

c)

11

d)

45

2.

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.

3.

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

4.
The number in front of a compound or element is a 
a)
Subscript
b)
Coefficient
c)
Superscript
d)
Charge
5.
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
6.
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
7.
Which is Chemical Equation is Balanced?
a)
CH₄+O₂------CO₂+2H₂O
b)
H₂+O₂-----2H₂O₄
c)
4Al+3O₂-----2Al₂O₃
8.
Which problem is balanced?
a)
PbO2 + 2H2
b)
SO2 + H20 --> H2SO4
c)
2Na + 2H2O --> 2NaOH + H2
9.
How many O's are in Al₂(SO₄)₃
a)
4
b)
12
c)
7
d)
24
10.
Which Chemical Equation is Balanced?
a)
CH₄+O₂------CO₂+2H₂O
b)
H₂+O₂-----2H₂O₄
c)
4Al+3O₂-----2Al₂O₃
11.
If a chemical reaction is EXOTHERMIC, the temperature would....
a)
Stay the same
b)
Increase
c)
Decrease
12.
During an endothermic reaction in a beaker if we are part of the surroundings and touched the beaker, it would feel _______. 
a)
Warm
b)
Cold
13.

What reaction has the following general formula:

A + CD --> C + AD

a)

Combination

b)

Decomposition

c)

Single Replacement

d)

Double Replacement

e)

Combustion

14.

What reaction has the following general formula:

AB --> A + B

a)

Combination

b)

Decomposition

c)

Single Replacement

d)

Double Replacement

e)

Combustion

15.

What reaction has the following general formula:
CxHy + O2 −>CO2 + H2OC_xH_y\ +\ O_2\ ->CO_{2\ }+\ H_2O  

a)

Combination

b)

Decomposition

c)

Single Replacement

d)

Double Replacement

e)

Combustion

16.

What type of reaction is the following:
2KI −> 2K + I22KI\ ->\ 2K\ +\ I_2  

a)

Combination

b)

Decomposition

c)

Single Replacement

d)

Double Replacement

e)

Combustion

17.

What type of reaction is the following:
C11H24+17O2−> 11CO2 + 12H2OC_{11}H_{24}+17O_2->\ 11CO_2\ +\ 12H_2O  

a)

Combination

b)

Decomposition

c)

Single Replacement

d)

Double Replacement

e)

Combustion

18.

What type of reaction is the following:
2NaHCO3−> Na2CO3+CO2+H2O2NaHCO_3->\ Na_2CO_3+CO_2+H_2O  

a)

Combination

b)

Decomposition

c)

Single Replacement

d)

Double Replacement

e)

Combustion

19.

What type of reaction is the following:
Zn + 2HCl −> ZnCl2+H2Zn\ +\ 2HCl\ ->\ ZnCl_2+H_2

a)

Combination

b)

Decomposition

c)

Single Replacement

d)

Double Replacement

e)

Combustion

20.
KOH + H3PO4 --> K3PO4 + H2O
a)
Synthesis (combination)
b)
Decomposition
c)
Single replacement
d)
Double replacement
21.
Si + S8 --> Si2S4
a)
Synthesis (combination)
b)
Decomposition
c)
Single replacement
d)
Double replacement
22.
What is the left part of a chemical equation called?
H2 + O → H2O
a)
Reactants
b)
Products 
c)
Yields 
d)
Chemical Equation 
23.
What does (aq) mean in a chemical reaction?
a)
Ag
b)
silver
c)
aqualirious
d)
aqueous
24.
What is the right part of a chemical equation called?
H2 + O → H2O
a)
Reactants
b)
Products 
c)
Yields 
d)
Chemical Equation 
25.
Which is the name of the kind of solid substance formed in this figure?  
a)
aqueous 
b)
precipitate
c)
acid
d)
synthesis 
26.
A precipitate is...
a)
a solid that falls out of a liquid solution
b)
a reactant in a reaction
c)
a clear substance
d)
the mass of a product
27.
A chemical reaction is...
a)
when a substance is mixed with another substance
b)
when a substance undergoes a change to form a new substance
c)
when a substance is dissolved into another substance
d)
when a substance is heated or exposed to another substance
28.
What is the term for the → sign in a reaction?
a)
makes
b)
produces
c)
yields
d)
all are correct
29.
Evidence of a chemical reactions is anything that shows - 
a)
a new substance has formed
b)
a solid dissolved in a liquid
c)
interaction between 2 gases
d)
a change in the state of matter
30.
Which is NOT an indication of a chemical change?
a)
temperature change
b)
formation of a precipitate
c)
shape change
d)
production of light
31.
You know you a chemical reaction has occurred if 
a)
there is a precipitate.
b)
there is a color change.
c)
there is a temperature change.
d)
All of these answers are evidence.
32.
A clear liquid from a flask is poured into another clear liquid in a beaker. Which of the following results of this procedure would indicate a new substance was formed?
a)
The level of the substance in the beaker is higher after the other liquid is added.
b)
A yellow solid forms and then settles to the bottom of the beaker.
c)
Small white crystals are left behind in the flask that held the first liquid.
d)
The mass of the combined liquids is greater than either original liquid.
33.
A student places a piece of a potato into a container of hydrogen peroxide. One observation the student makes is that bubbles form around the potato. The presence of bubbles might indicate the formation of a new substance because bubbles - 
a)
could show that a gas is forming.
b)
always rise to the top of a liquid. 
c)
are almost always perfectly spherical.
d)
usually burst after a few minutes.
34.
Which of the following is an example that includes evidence of a chemical reaction?
a)
A sample of zinc is placed in water and it settles to the bottom
b)
A solid block of ice is heated and it completely melts into a liquid. 
c)
Sugar that is burned gives off an odor and turns brown and then black.
d)
A tomato is placed into a blender and chopped up into smaller pieces.
35.

A chemical reaction that transfers energy from the reactants to the surroundings is referred to as

a)

exothermic

b)

endothermic

c)

paleothetic

d)

exergonic