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Law of Conservation of Mass

Total questions: 16

Worksheet time: 12mins

Name
Class
Date
1.

Which chemical equation supports the Law of Conservation of Matter?

a)

2H + O2 → 2H2O

b)

H2 + O2 → H2O

c)

H2 + O2 → 2H2O

d)

2H2 + O2 → 2H2O

2.

Alexandra is performing this combustion reaction in lab: C H + 5O → 3CO + 4H O. If she carefully measures out 220 g of C H and discovers that she has produced 660 grams of carbon dioxide and 360 g of water, how many grams of oxygen must have been required to react with the C H ?

a)

220 grams

b)

580 grams

c)

800 grams

d)

1240 grams

3.

A chemical reaction in which all of the reactants and products are gases takes place in a closed system. How would the chemical equation for that reaction be described?

a)

The mass of the product gases is equal to the mass of the reactant gases.

b)

The mass of the product gases is greater than the mass of the reactant gases

c)

The mass of the reactant and product gases will vary with the temperature.

d)

The mass of the reactant gases is greater than the mass of the product gases.

4.

A substance has one atom of sodium and one atom of chlorine. What is the chemical symbol for the element?

a)

NaCl

b)

H2O

c)

O2

d)

N2

5.

The mass of chemical A is 2 g, and the mass of chemical B is 5 g. If the two chemicals are mixed and a chemical reaction takes place, what is the mass of the end products?

a)

2 grams

b)

3 grams

c)

7 grams

d)

10 grams

6.

The chemical formula for ammonia is NH3 . What composes this compound?

a)

1 sodium and 3 helium atoms

b)

3 sodium and 3 hydrogen atoms

c)

3 nitrogen and 3 helium atoms

d)

1 nitrogen and 3 hydrogen atoms

7.

How is the Law of Conservation of Matter best represented in a chemical reaction?

a)

A The mass of the products is greater than the mass of the reactants.

b)

B The mass of the reactants is greater than the mass of the products.

c)

C The mass of the reactants is equivalent to the mass of the products.

d)

D The mass of the reactants has no relationship to the mass of the products.

8.

Which chemical equation is balanced to show that matter is conserved during the reaction?

a)

CaCO3 → CaCO2 + CO2

b)

C + H2O → CO + H2

c)

N2 + 3H2 → 3NH3

d)

SO2 + O2 → 2SO4

9.

Which chemical equation is balanced to show that mass is conserved during the reaction?

a)

H + Cl → HCl

b)

H2 + O2   → H2O

c)

H + Cl → 2HCl

d)

H2 + O2 → 2H2O

10.

How many atoms are found in 9 molecules of nitrogen gas?

a)

7

b)

9

c)

11

d)

18

11.

What is the 2 called in the reactants of the balanced equation H2 + Cl2 → 2HCl?

a)

subscript

b)

coefficient

c)

atomic number

d)

atomic mass

12.

Which chemical equation reflects the law of conservation of mass?

a)

CaCO3 → CaO2 + CO2

b)

C + H2O → CO + H2

c)

N2 + 3H2 → 3NH3

d)

SO2 + O2 → 2SO4

13.

What does the arrow represent in the chemical equation?

a)

breaks apart

b)

combines

c)

yields

d)

chemically reacts

14.

How many atoms are found in one molecule of Aluminum Phosphate which has a chemical formula AlPO4?

a)

3

b)

4

c)

5

d)

6

15.

The chemical formula for glucose is C6H12O6. How many atoms are found in one molecule of glucose?

a)

3

b)

4

c)

24

d)

25

16.

What is a reasonable hypothesis for an experiment that investigates the Law of Conservation of Mass?

a)

If two reactants are massed and combined, then the mass of the product will be the same as the combined masses of the reactants.

b)

If two reactants are combined, the total mass before and after the reaction can be  measured.

c)

How does the mass of the reactants compare to the mass of the products?

d)

What is the total mass of the products of a chemical reaction?