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Matter and composition

Total questions: 29

Worksheet time: 48mins

Name
Class
Date
1.

The law of definite proportion states...

a)

that pizza must be cut into 8 slices

b)

that moles of a liquid are always proportional to kilograms of a gas

c)

that a given chemical compound always contains its component elements in fixed ratio (by mass)

d)

that atoms are distributed proportionally on the periodic table

2.

Based on the law of definite proportion, how many atoms of phosphorous would be bonded to calcium in the compound calcium phosphide?

a)

3

b)

2

c)

1

d)

6

3.

The law of definite proportion tells us that for each barium atom we find in a compound of barium chloride we would find

a)

1 atom of Cl

b)

1 atom of C

c)

2 atoms of Cl

d)

2 atoms of C

4.

What is a hydrate?

a)

a compound with water in it

b)

a compound that has lost its water

c)

a hydrated compound

5.

When given moles of an element and asked for atoms of that element use:

a)

molar mass of the element

b)

formula units of the compound

c)

Avogadro's number

d)

a very tiny scoopula

6.

Matter can be transformed

a)

True

b)

False

7.

The law of conservation of mass states

a)

that mass is only created after having been destroyed

b)

that mass can be created but never destroyed

c)

that the mass contained within a White Castle slider can destroy the volume of air occupied in the White Castle bathroom

d)

that mass is never created or destroyed

8.

How many moles of water are in the following hydrate:

CuSO4 . 5H2O

a)

6

b)

1

c)

5

9.

molecular formulas are always empirical

a)

True

b)

False

10.

How many atoms of fluoride are there in 0.23 moles of iron(III) fluoride ?

a)

1.4 x 1023 atoms

b)

4.20 x 1023 atoms

c)

4.2 x 1023 atoms

d)

1.38 x 1023 atoms

11.

molecular formulas may, or may not be empirical

a)

True

b)

False

12.

Find the percentage composition of Mg in Mg3(PO4)2.

a)

27.75% Mg

b)

23.57% Mg

c)

48.68% Mg

d)

13.45% Mg

13.

formula units are always empirical

a)

True

b)

False

14.

How many atoms are there in 1.306 mol of Fe ?

a)

72.93 x 1022

b)

72.61

c)

7.86212 x 1023

d)

7.862 x 1023

15.

How many grams of sodium chloride are in 2.9 moles of sodium chloride?

a)

169.5 g

b)

169.51 g

c)

170. g

d)

1.7 x 102 g

16.

When 8.20 grams of magnesium burns it combines completely with 5.40 grams of oxygen the compound magnesium oxide is formed. What is the percent composition of each element in this compound?

a)

60.3% O, 39.7% Mg

b)

60% Mg, 40% O

c)

60.3% Mg, 39.7% O

d)

40% Mg, 60% O

17.

formula units may, or may not be empirical

a)

True

b)

False

18.

How many moles of iron are 2.85 x 1018 atoms of iron?

a)

3.26 x 10-2 mol

b)

1.38 mol

c)

4.73 x 10-6 mol

d)

0.007 mol

19.

How many formula units are in 3.55 moles of aluminum sulfate?

a)

2.1 x 1024 formula units

b)

2.14 x 1023 formula units

c)

2.14 x 1024 formula units

d)

2.1 x 1023 formula units

20.

If 4.87 g of a hydrate remains after heating and the percent water in the compound was 29.8%, what was the mass of the original compound?

a)

6.94 g

b)

0.0612 g

c)

6.9 g

d)

6.12 x 102 g

21.

How many molecules are in 31.8 moles of water?

a)

1.9 x 1023 molecules

b)

1.91 x 1023 mol

c)

1.91 x 1022 molecules

d)

1.91 x 1025 molecules

22.

600. grams CuSO4 . 5H2O is how many moles of hydrate?

a)

1.50 x105 mol

b)

149,832 mol

c)

2.4 mol

d)

2.40 mol

23.

How many moles are in 2.13 grams of carbon?

a)

1.77 x 10-1 mol

b)

0.17 mol

c)

25.6 mol

d)

26 mol

24.

How many grams of water would a student need to electrolyze in order to produce 2.700 x 104 grams of oxygen gas?

a)

3.04 x 102 g

b)

3.041 g

c)

30410 g

d)

3.041 x 104 g

25.

What is the percentage of chromium in K2Cr2O7?

a)

38.1%

b)

27.2%

c)

34.7%

d)

100%

26.
A 15.67 g sample of a hydrate of magnesium carbonate was heated to drive off the water. The mass was reduced to 7.58 g. What is the formula of the hydrate?
a)
MgCO3 · 5H2O
b)
MgCO3 · 4H2O
c)
MgCO3 · 6H2O
d)
MgCO3 · 1H2O
27.

Determine the molar mass for CCl4

a)

153.8 g/mol

b)

47.54 g/mol

c)

189.35 g/mol

d)

82.9 g/mol

28.
What is the molar mass of AuCl3?
a)
96 g
b)
130 g
c)
232.5 g
d)
303.3 g
29.

The law of definite proportion tells us that there are how many chlorine atoms present in 2 molecules of carbon tetrachloride?

a)

4

b)

3

c)

7

d)

8