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Law of Conservation of Matter

Total questions: 25

Worksheet time: 51mins

Name
Class
Date
1.
Balance this equation
_N2 + _H2 --> _NH3
a)
1,2,3
b)
1,3,2
c)
1,1,2
d)
2,1,1
2.
How many atoms of aluminum are on each side of the following equation: 4Al + 3O2 --> 2Al2 O3
a)
2
b)
6
c)
1
d)
4
3.
The coefficient in  3H2O is
a)
6
b)
2
c)
3
d)
5
4.

Which of the following are Subscripts in this Chemical Formula: 3Fe2O4

a)

3,4

b)

3,2

c)

2,4

d)

6

5.

Which section represents the reactants?

a)

A

b)

B

c)

C

6.

Why does this picture demonstrate the Law of Conservation of Mass?

a)

the number of atoms of each element are the same on both sides

b)

they start out separate and end up combined

c)

the same elements are used

d)

it doesn't demonstrate the Law of Conservation of Mass

7.

If a chemical reaction occurs in a closed system (no way for any part of the reaction to escape), how does the product mass compare to the reactant mass?

a)

the mass would decrease

b)

the mass would increase

c)

the mass would stay the same

d)

it depends on the type of reaction

8.

If a chemical reaction occurs in an open system (not contained), what might happen to the measurable mass of the products when compared to the reactants?

a)

the measurable mass might decrease because any gas produced can escape (the actual mass would stay the same)

b)

the mass would increase because mass was created

c)

the measurable mass would stay the same because nothing would be able to leave the system.

d)

it depends on the type of reaction

9.

Which picture below would correctly demonstrate the Law of Conservation of Matter if this picture is the reactants?

a)
b)
c)
d)
10.

Which of the following chemical equations are balanced? (check all that apply)

a)

2Mg + O2 --> 2MgO

b)

2Al2O3 --> 4Al + 3O2

c)

HgO --> 2Hg + O2

d)

Na + Br2 --> 2NaBr

e)

C + 2H2 --> CH4

11.

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

12.
O3 ---> O + O2
a)
Synthesis
b)
Single Replacement
c)
Decomposition 
d)
Combustion
13.
Which of the following shows the correct way to balance the chemical equation?
Fe + O2 -> Fe2O3
a)
4Fe + 3O2 -> 2Fe2O3
b)
2 Fe + 3O2 -> Fe2O6
c)
4 Fe + O6 -> 2Fe2O3
d)
None of the options are correctly balanced.
14.
Is the following equation balanced?
2C2H2 + 5O2 --> 4CO2 + 2H2O
a)
yes
b)
no
15.
Balance this equation
_Al +_HCl --> _H2 +_AlCl3
a)
2, 6, 3, 2
b)
it is already balanced
c)
4, 12, 3, 4
d)
2, 1, 4, 5
16.
When the equation H2O2 --> H2O + O2 is completely balanced, the coefficient for water is 
a)
5
b)
8
c)
3
d)
4
17.
Classify
Zn + H
2S → ZnS + H2
a)
synthesis
b)
combustion
c)
single replacement
d)
double replacement
18.

In a chemical equation, is it true that -

a)

the reactant side and product side can have different numbers of atoms for each element

b)

there can be different elements on the reactant side and the product side

c)

the reaction must always take place in a closed system in order for it to work

d)

the coefficients indicate the number of molecules of each reactant used and the number of molecules of each product made

19.
Balance this equation.
_Mg + _Cl2 --> _MgCl2
a)
1, 2,1
b)
already balanced
c)
2,1,1
d)
1,1,2
20.

Which type of reaction is:

2 NH3 + H2SO4 → (NH4)2SO4

a)
Synthesis
b)
Decomposition
c)
Single Displacement
d)
Double Displacement
21.

Which type of reaction is:

4 (NH4)3PO4 + 3 Pb(NO3)4 → 12 NH4NO3 + Pb3(PO4)4

a)
Synthesis
b)
Decomposition
c)
Single Displacement
d)
Double Displacement
22.

The symbol (g) found beside a chemical formula indicates that the chemical is ___________________.

a)

stable in composition

b)

instable in composition

c)

in the gaseous state

d)

an organic sugar

23.

Some chemical reactions require a substance called a catalyst. The purpose of a catalyst is

a)

to warm up the reaction

b)

to speed up the reaction

c)

to create more reactants

d)

to stop the reaction

24.

Which of the following is a common sign that a chemical change has occurred?

a)

A chemical has turned a different color, bubbled, and/or changed temperature.

b)

A chemical has changed to a different state of matter, such as a liquid to a solid.

c)

A chemical has changed size.

d)

A chemical has become a different shape.

25.
In an endothermic reaction, heat is ...
a)
taken in or absorbed
b)
given out or released