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Physical Science: Balancing Equations

Total questions: 44

Worksheet time: 44mins

Name
Class
Date
1.

What is the total mass of the reactants compared to the total mass of the products in a sealed reaction?

a)

the mass is the same

b)

the mass changes depending on the reaction

2.

What does the principle of conservation of mass mean when mixing vinegar and baking soda in a sealed container?

a)

Matter is not created or destroyed.

b)

The total mass of the reactants is less than the total mass of the products.

3.

The red numbers in the chemical equation represent ________

a)

coefficients

b)

I don't know, and don't want to try

4.

In a chemical equation, the blue numbers represent ________

a)

coefficients

b)

subscripts

5.

In a science experiment, Charlotte mixes vinegar and baking soda. The substances she starts with are called the ____

a)

reactants

b)

yield

6.

What is the right part of the chemical equation H2 + O2 --> H2O called?

a)

Yields

b)

Products

7.

What does the arrow in the recipe represent?

a)

Yields

b)

Reactants

8.

Kobe is trying to balance a chemical equation. He knows that a ____ can be placed to the left of a formula to make the equation balanced.

a)

coefficient

b)

random number

9.

Balance the equation: __Al + __O2--> __Al2O3

a)

4,3 --> 4

b)

4,3 --> 2

10.

Balance the chemical equation: __H2SO3 + __KOH --> __H2O + __K2SO3

a)

1,2 --> 2,1

b)

1,2 --> 1,2

11.

What is the right ratio of chemicals for the BCE (Balanced Chemical Equation)?__H2 + __S --> __H2S

a)

1,1 --> 1

b)

1,2 --> 2

12.

Balance the chemical equation: __AgNO3 + __H2S --> __Ag2S + __HNO3

a)

1,2 --> 1,2

b)

2,1 --> 1,2

13.

What is the term for the numbers in front of compounds to balance a chemical equation?

a)

Coefficients

b)

None of the above

14.

What are the substances formed from a chemical reaction called?

a)

Catalysts

b)

Products

15.

When Luna mixes two chemicals, the total mass remains the same. Which law is this?

a)

Law of Definite Proportions

b)

Law of Conservation of Mass

16.

Balance the chemical equation: __C2H6 + __O2 --> __CO2 + __H2O

a)

2,7 --> 4,6

b)

2,5 --> 4,6

17.

What are substances used up in a chemical reaction called?

a)

Reactants

b)

Inhibitors

18.

During a lab session, Mia observes that the total mass of the reactants equals the total mass of the products after a chemical reaction. Which scientific principle is she observing?

a)

Law of Conservation of Energy

b)

Law of Conservation of Mass

19.

What substances change in a chemical reaction?

a)

Catalysts

b)

Reactants

20.

During a chemistry experiment, Liam observes that the mass of the reactants equals the mass of the products. Which law is he observing?

a)

Law of Conservation of Energy

b)

Law of Conservation of Mass

21.

What are the numbers before chemical formulas in a balanced equation called?

a)

Exponents

b)

Coefficients

22.

Group 1 uses a balloon to contain gas from a baking soda and vinegar reaction, while Group 2 does not. How would the final mass in Group 2's experiment compare to Group 1's, and why?

a)

The final mass in Group 2's experiment will be greater than Group 1's, because mass is always added during chemical reactions.

b)

The final mass in Group 2's experiment will be less than Group 1's, because gas is allowed to escape the flask, decreasing the final mass.

23.

Which of the following is a correctly written chemical equation that demonstrates the conservation of mass?

a)

Mg + HCl ---> H2 + MgCl2

b)

H2O + CO2 ---> H2CO3

24.

In a reaction between baking soda and phenol in a plastic bag, what is TRUE about the mass after the reaction?

a)

The mass stayed the same from the beginning to the end.

b)

None of the choices are correct.

25.

Is this equation balanced?

a)

no

b)

yes

26.

Is this equation balanced?

a)

Yes

b)

No

27.

Which equation shows a chemical reaction forming a new substance?

a)

D

b)

A

28.

Is the chemical equation balanced?

a)

Yes

b)

No

29.

What coefficient belongs in the red box to balance the equation?

a)

0

b)

2

30.

In chemical reactions, what does the conservation of mass mean?

a)

Matter is not created or destroyed.

b)

The total mass of the reactants is less than the total mass of the products.

31.

Balance the chemical equation: __C3H8 + __O2 --> __CO2 + __H2O. What is the correct ratio of coefficients?

a)

2,7 --> 6,8

b)

1,5 --> 3,4

32.

Which problem is balanced?

a)

SO2 + H2O --> H2SO4

b)

2Na + 2H2O --> 2NaOH + H2

33.

Balance this equation
_Al +_HCl --> _H+_AlCl3

a)

2, 6, 3, 2

b)

2, 1, 4, 5

34.

How many atoms of aluminum are on each side of the equation: 4Al + 3O2 --> 2Al2O3?

a)

4

b)

2

35.

How many carbon atoms are in C6H12O6?

a)

6

b)

3

36.

How many atoms are in H2SO4?

a)

7

b)

5

37.

What is the little number after an element in a chemical equation called?

a)

Subscript

b)

Atom

38.

Which problem is balanced?

a)

SO2 + H2O --> H2SO4

b)

2Na + 2H2O --> 2NaOH + H2

39.

Balance this equation.
_SnO2 + _H2 --> _Sn + _H2O

a)

1,2,1,1

b)

1,2,1,2

40.

Determine the coefficients to balance the equation.

__Al +__HCl --> __H2 +__AlCl3

a)

2,6,3,2

b)

it's already balanced

41.

How many HCl molecules are needed to balance the equation?

Mg + __HCl ---> MgCl2 + H2

a)

2

b)

3

42.

Determine the coefficients to make the following equation balanced?

__N2 + __O2--> __NO

a)

1, 1, 1

b)

1, 1, 2

43.

In a chemical reaction, what happens to atoms?

a)

Nothing Happens

b)

Atoms rearrange

44.
Since gasses weigh nothing, when they are produced in a reaction they do not have to be accounted for.  
a)
True
b)
False