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Homework 20 - Chemical Reactions - Due 04/10

Total questions: 15

Worksheet time: 31mins

Name
Class
Date
1.

The Law of Conservation of Mass says that matter cannot be ________ or __________.

a)

Divided or Multiplied

b)

Balanced or Unbalanced

c)

Increased or Decreased

d)

Created or Destroyed

2.

Which of the following can by possible physical indicators of a chemical reaction?

a)

Formation of Gas

b)

Change in Color

c)

Emission of Light

d)

Sublimation of Solids

e)

Deposition of Gases

3.

Reactants are the chemicals that are present at the beginning of an experiment. Reactants react together to make the product.

We can know that a chemical reaction is occurring when we see ______.

a)

that the product looks just like the reactants.

b)

nothing new.

c)

that the product looks different from the reactants.

4.

Which of the following is evidence of a chemical reaction?

a)

Tearing paper.

b)

Change in color.

c)

Production of a gas.

d)

Change in temperature.

e)

Production of a precipitate.

5.

How many Carbons are present on the reactant side?

a)

1

b)

2

c)

3

d)

4

6.

Why are chemical equations always balanced? Select ALL that apply.

a)

Matter cannot be created.

b)

Matter cannot be destroyed.

c)

Matter can only be rearranged/conserved.

d)

Matter doesn't matter.

7.

How many Hydrogens are on the product side of this chemical equation?

a)

1

b)

2

c)

3

d)

4

8.

What does it mean for a reaction to be endothermic? Choose 2 of the following.

a)

When two substances react, the temperature of the mixture decreases.

b)

When two substances react, the temperature of the mixture increases.

c)

There is less energy going into the reactant to break the bond than there is energy leaving the product.

d)

There is more energy going into the reactant to break the bond than there is energy leaving the product.

e)

The amount of energy entering and leaving is the same.

9.

What does it mean for a reaction to be exothermic? Choose 2 of the following.

a)

When two substances react, the temperature of the mixture decreases.

b)

When two substances react, the temperature of the mixture increases.

c)

There is less energy going into the reactant to break the bond than there is energy leaving the product.

d)

There is more energy going into the reactant to break the bond than there is energy leaving the product.

e)

The amount of energy entering and leaving is the same.

10.
In a chemical reaction
a)
The atoms of the reactants always stay together to form the products
b)
The atoms of the reactants unbond, rearrange, and then rebond to form the products
c)
New atoms are formed which combine to make the products
d)
Some atoms disappear while others multiply to form the products
11.

Look at the chemical equation.


How many atoms of mercury (Hg) are in the reactants?

(a)  

12.

Look at the chemical equation.


How many atoms of nitrogen (N) are in the products?

(a)  

13.
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
14.
If a chemical reaction is EXOTHERMIC, the temperature would....
a)
Stay the same
b)
Increase
c)
Decrease
15.

The reactants in the image above are:

a)

CH4 and 2 O2

b)

2 H2O and CO2

c)

All of these are reactants

d)

All of these are products