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Holy Moly 6.0-6.4

Total questions: 88

Worksheet time: 10hrs 6mins

Name
Class
Date
1.

  1. Which molecular formula is correctly paired with its corresponding empirical formula?

a)

  1. CO2 and CO

b)

  1. C2H2 and CH2

c)

  1. C6H6 and C2H2

d)

  1. P4O10 and P2O5

2.

  1. What is the empirical formula for C3H6?

a)

  1. CH

b)

  1. CH2

c)

  1. CH3

d)

  1. CH6

3.

  1. What is the empirical formula for the compound C6H12O6?

a)

CH2O

b)

C2H4O2

c)

C3H6O3

d)

C6H12O6

4.

  1. The formula H2O2 is an example of

  2. Hint: To see if it's an EF, ask yourself: Are the elements in the lowest ratio possible to each other?

  3. (Meaning, is there any number you can divide both of them by and still get a whole number for each? )

a)

molecular formula

b)

empirical formula

c)

ionic formula

d)

organic formula

5.

  1. What is the gram formula mass of Na2CO3 • 10H2O?

  3. *GRAM FORMULA MASS (g/mol) = MOLAR MASS (g/mol)

a)

106 g/mol

b)

142 g/mol

c)

266 g/mol

d)

286 g/mol

6.

What is the gram formula mass of Li2SO4?

a)

54 g/mol

b)

55 g/mol

c)

110 g/mol

d)

206 g/mol

7.

What is the formula mass of Li2SO4?

a)

54 g/mol

b)

54 amu

c)

55 g/mol

d)

110 g/mol

e)

110 u

8.

  1. Which substance has the greatest molecular mass?

a)

I2

b)

H2O2

c)

CF4

d)

NO

9.

  1. Which represents the greatest mass of chlorine?

a)

1 atom of chlorine

b)

  1. 1 mole of chlorine

c)

1 molecule of chlorine

d)

1 gram of chlorine

10.

What is the total number of atoms of oxygen in the formula Al(ClO3)3 • 6H2O?

a)

6

b)

9

c)

10

d)

15

11.

How many moles of water are contained in 0.250 mole

of CuSO4 • 5H2O?

Hint: Don't be scared of hydrates, it's the same process as if you were looking for how many moles of an element in a given amount of substance: Multiply amount of substance by the moles of what you are looking for

a)

1.25 mol

b)

4.50 mol

c)

40 mol

d)

62.5

12.

What is the total mass of oxygen in 1.00 mole of Al2(CrO4)3?

a)

192 g

b)

112 g

c)

64.0 g

d)

48.0 g

13.

The total number of moles represented by 20 grams of CaCO3 is

a)

1

b)

2

c)

.1

d)

.2

14.

What is the total mass in grams of 0.75 mole of SO2?

a)

16 g

b)

24 g

c)

32 g

d)

48 g

15.

If the empirical formula for an organic compound is CH2O, then the molecular mass of the compound could be

Strategy: First, see if any of the masses given = the molar mass of the given

If not, start playing with multiplies , write the formula you get first, then get the MM of what you made and see if it equals an answer choice

Start with low numbers

a)

135 g/mol

b)

60 g/mol

c)

45 g/mol

d)

15 g/mol

16.

A compound has an empirical formula of CH2 and a

molecular mass of 56. What is its molecular formula?

a)

CH2

b)

C2H4

c)

C3H6

d)

C4H8

17.

A sample of an unknown gas at STP has a density of 1.25 grams per liter. What is the gram molecular mass of this gas?

1 mol of a gas = 22.4 L

a)

28.0 g

b)

44.0 g

c)

64.0 g

d)

80.0 g

18.

  1. A compound consists of 40.% sulfur and 60.% oxygen by mass. What is the empirical formula of this compound?

How many g of S in 100 g? How many g O in 100 g?

How many moles S? How many moles O?

Which is the lower number of moles -> divide both by that!

Do you get a whole number? Yes: Congratulations! No: Multiply by smallest multiple..,

a)

SO

b)

SO2

c)

SO3

d)

SO4

19.

  1. What is the empirical formula of a compound that contains 30.4% nitrogen and 69.6% oxygen by mass?

  2. Hint: % are the magic manifestations of the beauty of what makes a compound a compound -use them!

  3. -How many grams of N would be in a 100 grams sample? How many grams of O?

  4. -How many moles of N would you have? How many moles of O?

  5. Divide by the lower number of moles!

  6. Did you get a whole number -GREAT! I If not, multiply by smallest multiple!

a)

  1. NO

b)

NO2

c)

  1. N2O3

d)

  1. N2O5

20.

A compound consists of 25.9% nitrogen and 74.1% oxygen by mass. What is the empirical formula of the compound?

Check answer explanation this has several steps

a)

NO

b)

NO2

c)

N2O

d)

N2O5

21.

  1. What is the percent by mass of carbon in CO2?

a)

12%

b)

27%

c)

44%

d)

73%

22.

  1. What is the percent composition by mass of nitrogen in

    NH4NO3 (gram-formula mass = 80.0 grams/mole)?

a)

  1. 17.5%

b)

  1. 35.0%

c)

  1. 52.5%

d)

  1. 60.0%

23.

  1. What is the approximate total number of atoms in 1.0

    mole of lithium?

a)

  1. 1.0 × 1023

b)

  1. 6.0 × 1023

c)

3.0

d)

6.9

24.

  1. How many molecules are in 0.25 mole of O2?

a)

12 × 1023

b)

6.0 × 1023

c)

3.0 × 1023

d)

1.5 × 1023

25.

  1. What is the total volume occupied by 132 grams of CO2 (g) at STP?

  3. Hint: Check your mole maps in your unit outline (front and back of it)

    22.4 L = 1 mol

a)

  1. 22.4 L

b)

  1. 33.6 L

c)

  1. 44.8 L

d)

  1. 67.2 L

26.
Which pair has the same empirical formula?
a)
NaCrO4 and Na2Cr2O7
b)
C2H4O2 and C6H12O6
c)
C3H6O3 and C2H6O2
d)
CH4 and C2H6
27.
What is the molecular formula if the empirical formula is CH2O and the molecular molar mass is 180.18?
a)
CH2O
b)
C2H4O2
c)
C4H8O4
d)
C6H12O6
28.


  1. Which sample contains the same number of atoms as 24 grams of carbon?

  2. Hint: This is easier than you might think. You can use a picket fence/DA but you don't need to if you understand what a mole is and how that relates to other units like atoms....

a)

10. g Ne

b)

80. g Ar

c)

24 g Mg

d)

4.0 g He

29.

A compound contains 53% Al and 47% O by mass. What is the empirical formula of this compound?

a)

Al3O2

b)

Al2O3

c)

AlO2

d)

AlO

30.

Which formula is both a molecular and an empirical formula?

a)

C6H12O6

b)

C3H8O

c)

C4H8

d)

C2H4O2

31.

What is the empirical formula of a compound that contains 28% iron, 24% sulfur, and 48% oxygen by mass?

a)

Fe2(SO3)3

b)

FeSO4

c)

Fe2(SO4)3

d)

FeSO3

32.

The sum of the atomic masses of the atoms in one molecule of C3H6Br2 is called the

a)

formula mass

b)

percent composition

c)

isotopic mass

d)

percent abundance

33.

One mole of bromine gas, Br2, has a mass of

a)

35.0 g

b)

70.0 g

c)

79.9 g

d)

159.8 g

34.

What is the percent composition by mass of nitrogen in the compound N2H4 (gram-formula mass = 32 g/mol)?

a)

13%

b)

44%

c)

88%

d)

93%

35.

What is the number of moles of CO2 in a 220. gram sample of CO2 ?

a)

0.200 mol

b)

5.00 mol

c)

15.0 mol

d)

44.0 mol

36.

What is the number of moles of KF in a 29 gram sample of the compound?

a)

1.0 mol

b)

2.0 mol

c)

0.50 mol

d)

5.0 mol

37.

Given the balanced equation representing a reaction: 2Na(s) + Cl2(g) → 2NaCl(s) + energy If 46 grams of Na and 71 grams of Cl2 react completely, what is the total mass of NaCl produced?

Hint: Think Conservation of Mass!

a)

58.5 g

b)

117 g

c)

163 g

d)

234 g

38.

Given two formulas representing the same compound:

Formula A CH3

Formula B C2H6

Which statement describes these formulas?

a)

Formulas A and B are both empirical.

b)

Formulas A and B are both molecular.

c)

Formula A is empirical, and formula B is molecular.

d)

Formula A is molecular, and formula B is empirical.

39.

Which compound contains the greatest percentage of chlorine by mass?

a)

HCl

b)

FeCl2

c)

NaCl

d)

ZnCl2

40.

What is the total number of oxygen atoms in the formula MgSO4 • 7 H2O?

[The • represents seven units of H2O attached to one unit of MgSO4

a)

11

b)

7

c)

5

d)

4

41.

What is the total number of moles of oxygen atoms in the formula MgSO4 • 7 H2O?

[The • represents seven units of H2O attached to one unit of MgSO4

a)

11

b)

7

c)

5

d)

4

42.

The number of moles of molecules in a 12 gram sample of Cl2 is

Hint: Draw your picket fence and see which presentation would get you the same answer :)

This is how "they" try to trick students - you know the most effective ways to solve is to draw the fence out every single time - follow your fence it will take you wherever you need to go (if you set it up right)

a)

12. mol

35.

b)

12. mol

71.

c)

12 mol

d)

12 x 35.5 mol

43.

A sample of a substance containing only magnesium and chlorine was tested in the laboratory and was found to be composed of 74.5% chlorine by mass. If the total mass of the sample was 190.2 grams, what was the mass of the magnesium?

a)

24.3 g

b)

48.5 g

c)

70.9 g

d)

142 g

44.

A hydrate is a compound that includes water molecules within its crystal structure. During an experiment to determine the percent by mass of water in a hydrated crystal, a student found the mass of the hydrated crystal to be 4.10 g. After heating to constant mass, the mass was 3.70 g. What is the percent by mass of water in this crystal?

Think: Percent composition is (part/whole) x 100 and conservation of mass

a)

97.0%

b)

11.6%

c)

9.76%

d)

0.40%

45.

What is the total number of moles of atoms represented by the formula Al(C2H3O2)3

a)

22

b)

11

c)

8

d)

4

46.

How many grams are in 4.5 moles of CO2

a)

44.1 g/mol

b)

198 g/mol

c)

44.1 g

d)

198 g

47.

How many moles are in 12 grams of H2O?

a)

6.0 mol

b)

.67 mol

c)

18 mol

d)

12 mol

48.

  1. How many formula units are in 3 moles of NaF?

  3. Remember formula unit is what we use for ionic compounds

  4. treat formula unit like you would the term molecules or particles, etc.

  5. moles -> particles

a)

181 formula units

b)

1.26 x 1025 formula units

c)

3.00 formula units

d)

1.81 x 1024 formula units

49.

How many grams of NaF in 1.81 x 1024 formula units of NaF?

Hint: Treat formula units like you would particles or molecules

Hint 2: Think of the mole map...you have at least 2 of them (maybe more) in your unit outline! Can we go from particles/molecules/atoms/formula units directly to grams or do we have to stop at Mrs. Mole's house first? :)

a)

.300 g

b)

126. g

c)

1.35 x 1021 g

d)

44.8 g

50.

  1. How many moles make up 1.2 x 1024 atoms of carbon?

a)

2

b)

3

c)

1.2

d)

12

51.

How many molecules are in 100 grams of CH4?

a)

3.76 x 1024

b)

16.0 x 1022

c)

6.25

d)

6.25 x 1023

52.

The Ostwald process is an industrial method to produce nitric acid, HNO3(aq), used in the manufacture of fertilizers. Several steps are involved in this process. In the first step, ammonia and oxygen react in the presence of a catalyst, as represented by unbalanced equation 1.

Equation 1:  NH3 +  O2 --> NO  + H2O + heat

In the second step, nitrogen (II) oxide reacts with oxygen to produce nitrogen(IV) oxide, represented by balanced equation 2 below.

Equation 2  2NO + O2 --> 2NO2 + heat Determine the percent composition by mass of nitrogen in HNO3 (gram formula mass =63.0g/mol).

a)

12.5%

b)

22.2%

c)

25.0%

d)

14.0%

53.
What is the molecular formula if the empirical formula is CH2O and the molecular molar mass is 180.18?
a)
CH2O
b)
C2H4O2
c)
C4H8O4
d)
C6H12O6
54.
How many atoms of iodine are in a mole of iodine?
a)
53
b)
63.55g
c)
126.9
d)
6.02 x 1023
55.
What is the mass of 0.75 moles of (NH4)3PO4?
a)
101.75 g
b)
121.75 g
c)
111.75 g
d)
131.75 g
56.
If I need 20.4 moles of sodium chloride, how much should I weigh out?
a)
0.549 g
b)
112 g
c)
1192 g
d)
5077 g
57.

How many molecules would be in 8.4 moles of Octane (C8H18)?

a)

5.77 x 1023

b)

5.04 x 1024

c)

5.77 x 1026

d)

5.04 x 1023

58.
How many molecules are in 32.4 grams of phosphorous pentoxide?
a)
1.76 x 1023 molecules
b)
0.29 moles
c)
1.76 x 1022 molecules
d)
0.29 molecules
59.
Which has more molecules?
a)
1 mole H2O
b)
1 mole Al(OH)3
c)
1 mole NaCl
d)
There are all the same
60.
Where do you look to calculate the molar mass?
a)
avogadros number
b)
periodic table 
61.

How many moles are in 4.5x1024 Silver atoms?

a)

0.747 particles

b)

0.747 mol

c)

2.71x1047 mol

d)

2.71x1047 particles

62.
How many moles of carbon atoms are there in 5g of carbon?
a)
60 mol
b)
17 mol
c)
0.42 mol
d)
7 mol
63.
How many molecules are there in 5.9 moles of NaCl?
a)
3.5x1024molecules
b)
9.79x10-24molecules
c)
1.02x1023molecules
64.
How many molecules are present in 25 g of NaBr?
a)
102.96 molecules
b)
0.24 molecules
c)
1.45x1023 molecules
d)
2.34 x 1020molecules
65.
What is the mass of 0.89 mol of CaCl2?
a)
111 grams
b)
0.008 grams
c)
98.9 grams
d)
none of the choices
66.

How many grams are in 2.4 moles of Sulfur?

a)

76.8

b)

0.075

c)

13.3

d)

32

67.
The mass of one mole of substance is called...
a)
molecular mass
b)
mole constant
c)
molar mass
d)
atomic weight
68.

What is the molar mass of PbSO4?

a)

303.27 g/mol

b)

255.27 g/mol

c)

163.87 g/mol

d)

372.27 g/mol

69.

What is the mass of one mole of silver?

a)

32.06 g

b)

107.87 g

c)

14.01 g

d)

22.99 g

70.
How many moles are in 3.01 x 1022 atoms of magnesium?
a)
0.05 moles
b)
1.81 x 1046 moles
c)
5.00 x 1021 moles
d)
5 moles
71.
What is the percent by mass of oxygen in MgO?
a)
20%
b)
40%
c)
50%
d)
60%
72.
What is the percent by mass of sodium in NaCl?
a)
39%
b)
61%
c)
35%
d)
65%
73.
What is the percent composition by mass of sulfur in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
74.
What is the percent composition by mass of oxygen in the compound MgSO4 (gram formula mass = 120 g/mol)?
a)
20%
b)
27%
c)
46%
d)
53%
75.
What is the percent composition of Benzene, C6H6?
a)
C = 50%
H = 50%
b)
C = 85.7 %
H = 14.3%
c)
C = 92.2%
H = 7.8%
d)
C = 71.9%
H = 28.1%
76.
What is the empirical formula for C3H8
a)
CH
b)
C3H8
c)
C6H16
d)
CH2.7
77.

What is the empirical formula for a compound that is 40% Carbon, 6.70% Hydrogen and 53.3% oxygen?

Hint*(remember to assume 100 g sample)

a)

CHO

b)

CH2O

c)

CH3O

d)

CH2O2

78.

Indigo the dye used to color blue jeans is prepared using sodium amide. Sodium amid contains the following percentages by mass of the following elements: 5.17% Hydrogen, 35.9% Nitrogen and 58.9% sodium. What is the empirical formula for Sodium amide?

a)

NaNH

b)

Na2NH

c)

NaNH2

d)

NaN2H2

79.
Find the percent composition of Cu2S?
a)
%Cu= 67.987 %S= 32.013
b)
%Cu= 79.854   %S= 20.145
c)
%Cu= 35.946   %S= 64.054
80.

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


a)

27.48% Mg

b)

43.11% Mg

c)

16.00% Mg

d)

12.63% Mg

81.
What is the mass of one mole of aluminum?
a)
27 g
b)
13 g
c)
54 g
d)
14 g
82.
What is the percent by mass of fluorine in CaF2 (gram-formula mass = 78 g/mol)?
a)
24%
b)
49%
c)
51%
d)
65%
83.

Which element in the compound potassium cyanide, KCN, has a percent composition of 60.97%?

a)

K

b)

C

c)

N

d)

None of the above

84.
A formula with the lowest whole # ratio of elements in a compound is called
a)
Molecular Formula
b)
Chemical Formula
c)
Empirical Formula 
d)
Distance Formula
85.
Which of the following is considered an empirical formula?
a)
CH3COOH
b)
C6H12O6
c)
H2O
86.

What percent of Zn3(PO4)2 is zinc?

a)

33.15%

b)

16.04%

c)

50.80%

d)

19.68%

87.

What is the percent composition of a compound that contains 40.8 g carbon and 54.4 g oxygen?

a)

42.9 %; 57.1% oxygen

b)

52.9 %; 57.1% oxygen

c)

42.9 %; 45.23% oxygen

d)

55.9 %; 99.1% oxygen

88.

Find the percent composition of CaCl2?

a)

Ca: 36.11%; Cl: 63.88%

b)

Ca: 53.12%; Cl: 100%

c)

Ca: 36.11%; Cl: 83.56%

d)

Ca: 46.11%; Cl: 63.88%

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