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mole and formulae

Total questions: 60

Worksheet time: 5hrs 0mins

Name

Class

Date

Diagram shows a box of aspirin which can relieve fever and pain. If the molecular formula of aspirin is C₉H_XO₄, determine the value of x.

(a)

Which of the following gases contains 0.4 mol of atoms at room temperature and pressure?

[1 mol of gas occupies the volume of 24 dm³ at room temperature and pressure]

4.8 dm³ He

4.8 dm³ H₂

4.8 dm³ SO₃

4.8 dm³CO₂

A compound with formula XCO₃ has a relative formula mass of 125. What is the relative atomic mass of X? [Ar C = 12 and O = 16]

Calculate the volume of carbon dioxide gas produced for a complete combustion of 30 g of ethane gas at STP. [Ar H = 1, C = 12, 1 molar volume 22.4 dm³ mol^-1 at STP]

22.4 dm³

44.8 dm³

67.2 dm³

89.6 dm³

What is the molecular formula if the empirical formula is CH₂O and the molecular molar mass is 180?

CH₂O

C₂H₄O₂

C₄H₈O₄

C₆H₁₂O₆

What is the number of moles of hydrogen atoms in 1.7 g of ammonia gas (NH₃)?

0.1

0.3

1.4

1.7

The mass of one mole of oxygen atoms is 16 g. What is the mass of one mole of oxygen gas?

8 g

16 g

24 g

32 g

0.8 g of sodium hydroxide is dissolved to form a 250 cm³ aqueous solution. What is the concentration of this solution?

0.02 mol/dm³

0.08 mol/dm³

0.04 mol/dm³

0.80 mol/dm³

Which of the following solutions of hydrochloric acid has the highest concentration?

0.10 mol of HCl in 0.10 dm³ of solution

0.10 mol of HCl in 1.00 dm³of solution

36.5 g of HCl in 0.10 dm³ of solution

36.5 g of HCl in 1.00 dm³ of solution

10.

Calculate the relative molecular mass of H₂SO₄.

(a)

11.

Calculate the mass (in gram) of five moles of H₂SO₄.

(a)

12.

A sample of methane (CH₄) has a volume of 12 dm³ at room temperature and pressure. Calculate the number of moles of CH₄ in the sample

(a)

13.

The concentration of a sulfuric acid solution is 0.25 mol/dm³. What is the concentration of this acid in g/dm³?

(a)

14.

The concentration of a solution of hydrochloric acid is 73 g/dm³. What is the concentration of this acid in mol/dm³?

(a)

15.

How many molecules are there in 31.8 moles of water?

5.28 x 10^-23 molecules

1.91 x 10²⁵ molecules

5.28x 10-²⁵

1.91 x 10²²

16.

To melt the ice, Juan throws 455 g of calcium chloride, CaCl₂ on his sidewalk. How many moles of CaCl₂ did he throw?

50,500 moles

4.10 moles

7.56 x 10^-22 moles

111 moles

17.

Considering the UNBALANCED reaction:

Fe₂O₃(s) + CO(g) --> Fe(s) + CO₂(g)

How many moles of carbon dioxide are produced from 5.5 moles of carbon monoxide?

5.5 moles

2.75 moles

11 moles

7 moles

18.

The following is a chemical equation:

H₂SO₄(aq) + 2KOH(aq) → K₂SO₄(aq) + xH₂O(l)

What is the value of x?

19.

The complete burning of ethanol is as follows.

C₂H₅OH(l) + 3O₂(g) → 2CO₂(g) + 3H₂O(l)

What is the volume of oxygen gas needed at room conditions to burn 9.2 g of ethanol completely?

[Ar H = 1, C = 12, O = 16; Molar volume = 24 dm³ mol^-1 at room temperature and pressure]

4.8 dm³

9.6 dm³

14.4 dm³

19.2 dm³

20.

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?

[Ar H = 1, C = 12, O = 16, Mg = 24]

MgCO₃·5H₂O

MgCO₃·4H₂O

MgCO₃·6H₂O

MgCO₃·1H₂O

21.

2 NaClO₃ (s) --> 2NaCl (s) + 3O₂ (g)

12.00 moles of NaClO₃ will produce how many grams of O₂?

[Ar O = 16, Na = 23, Cl = 35.5]

256 g O₂

576 g O₂

288 g O₂

345 g O₂

22.

B₂H₆ + 3O₂ --> 2HBO₂ + 2H₂O

How many molecules of O₂ will be needed to burn 36.1 g of B₂H₆?

[Ar H = 1, B = 11, O = 16; Avogadro Constant, N_A = 6.02x10²³ mol^-1]

1.38 x 10²³ molecules O₂

3.86 x10²³ molecules O₂

2.33 x 10²⁴ molecules O₂

3.45 x 10²⁴ molecules O₂

23.

Using the following equation:
Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(l)
How many moles of iron can be made from 6 moles H₂?

4 moles Fe

6 moles Fe

9 moles Fe

2 moles Fe

24.

How many moles of nitrogen gas are in 135 dm³ of nitrogen gas at Standard Temperature and Pressure (STP)?

[Molar volume of gas at STP = 22.4 dm³ mol^-1]

9.64 moles of N₂

5.53 moles of N₂

6.03 moles of N₂

4.82 moles of N₂

25.

Table below shows the percentage by mass of each element in a compound and their relative atomic masses.

What is the empirical formula of the compound?

CHO

CHO₂

CH₂O

C₂HO

26.

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

(atomic mass Mg = 24; N = 14)

Mg₄N₃

MgN₂

Mg₃N₂

MgN

27.

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

(atomic mass C = 12; H = 1; O = 16)

C₂H₃O₂

CH₂O

C₂H₄O₂

C₃H₈O₃

28.

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

(atomic mass C = 12, H = 1; N = 14; O = 16)

What is the empirical formula of J?

C₄HNO₂

CH₂N₂O

C₂HNO₂

CHNO

29.

Which pair has the same empirical formula?

NaCrO₄ and Na₂Cr₂O₇

C₂H₄O₂ and C₆H₁₂O₆

C₃H₆O₃and C₂H₆O₂

CH₄ and C₂H₆

30.

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

(atomic mass S = 32; O = 16)

SO₂

SO₃

SO₄

31.

Find the molecular formula of CH₂ if its molar mass is 56.

(Ar C = 12, H = 1)

C2H8

C4H8

32.

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

(atomic mass Mg = 24; N = 14)

Mg₄N₃

MgN₂

Mg₃N₂

MgN

33.

Which of the following is considered an empirical formula?

CH₃COOH

C₆H₁₂O₆

H₂O

34.

You are given the following percentages: 40.05% S and 59.95% O. Find the empirical formula for these elements.

(atomic mass S = 32; O = 16)

SO2

SO3

SO4

35.

How many molecules are in 2.5 mol of NaCl?

1.5 x 10²⁴molecules

1.5 molecules

4.15 molecules

1.5 x 10²³molecules

36.

Which pair has the same empirical formula?

NaCrO₄ and Na₂Cr₂O₇

C₂H₄O₂ and C₆H₁₂O₆

C₃H₆O₃and C₂H₆O₂

CH₄ and C₂H₆

37.

A compound consists of 72.2% magnesium(Mg) and 27.8% nitrogen(N) by mass. What is the empirical formula?

(atomic mass Mg = 24; N = 14)

Mg₄N₃

MgN₂

Mg₃N₂

MgN

38.

A formula with the lowest whole # ratio of elements in a compound is called

Molecular Formula

Chemical Formula

Empirical Formula

Distance Formula

39.

Glycerol has a molar mass of 92.09g/mol. Its percent composition is: 39.12% C, 8.75% H, and 51.12% O. What is the molecular formula for glycerol?

(atomic mass C = 12; H = 1; O = 16)

C₂H₃O₂

CH₂O

C₂H₄O₂

C₃H₈O₃

40.

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

(atomic mass C = 12; H = 1; N = 14; O = 16)

What is the empirical formula of J?

C₄HNO₂

CH₂N₂O

C₂HNO₂

CHNO

41.

2.40 g of an explosive, J, contains 0.473 g of nitrogen. J also contains 33.8% carbon and 1.41% hydrogen by mass. The remainder of J is oxygen.

(atomic mass C = 12; H = 1; O = 16; N = 14)

What is the empirical formula of J?

C₄HNO₂

CH₂N₂O

C₂HNO₂

CHNO

42.

What is the empirical formula of a substance with the molecular formula C₂H₄?

C₂H₂

C₁H₁

CH₂

43.

What is the empirical formula of a substance with the molecular formula NaCl?

Na₂Cl

NaCl₂

NaCl

Na₂Cl₂

44.

What is the empirical formula of a substance with the molecular formula X₂₀Y₁₅?

X₁₀Y₁₅

X₅Y₃

X₄Y₃

X₂₀Y₁₅

45.

What is the empirical formula of a substance with the molecular formula Se₈F₁₂?

Se₈F₁₂

Se₂F₃

Se₄F₃

SeF

46.

What is the empirical formula of this substance?

C₂H₃

CH₃

C₂H₆

C₂H₂

47.

What is the empirical formula for hydrogen peroxide (H₂O₂)?

H₂O

H₂O₂

HO₂

48.

Which pair has the same empirical formula?

NaCrO₄ and Na₂Cr₂O₇

C₂H₄O₂ and C₆H₁₂O₆

C₃H₆O₃and C₂H₆O₂

CH₄ and C₂H₆

49.

Napthalene has the chemical formula C₁₀H₈. What would be the empirical formula?

C₁₀H₈

C₅H₄

C₂₀H₁₆

CH₂

C₄H₃

50.

Glucose has the formula C₆H₁₂O₆. Maltose has the chemical formula C₁₂H₂₂O₁₁. Do the have the same empirical formula?

Yes

51.

Which of these is NOT an empirical formula?

CH2

C2H5

C6H4

C3H7

C5H17

52.

How many moles are 98.3 grams of aluminum hydroxide, Al(OH)₃? (Atomic mass of Al = 27, H= 1, O = 16)

1.26 moles

0.8 moles

7,673.4 moles

150 moles

53.

How many atoms are contained in 25 g of NaBr? (Atomic mass of Na = 23, Br = 35)

102.96 molecules

0.24 molecules

1.45x10²³ molecules

2.34 x 10²⁰molecules

54.

Identify the number of Chlorine atoms in 65.8 g CaCl_2.

(atomic mass Ca = 40 and Cl = 35.5)

7.14 x 10²³ atoms

8.71 x 10²³ atoms

1.22 x 10²³ atoms

3.57 x 10²³ atoms

55.

How many moles are 98.3 grams of aluminum hydroxide, Al(OH)₃? (Ar Al=27, H=1, O=16)

1.26 moles

0.8 moles

7,673.4 moles

150 moles

56.

How many grams of silicon (atomic mass = 28.1 amu) would there be in a sample that contained 9.99 x 10²² atoms?

1.69 g

4.66 g

1.66 g

1.79 g

57.

There are 5.6 liters of nitrogen gas at STP condition. What is the number of mole of nitrogen gas?

(Ar N = 14 gram/mole)

0.10 mole

0.15 mole

0.20 mole

0.25 mole

0.30 mole

58.

What amount (in moles) is present in 2.0 g of sodium hydroxide, NaOH? (Mr NaOH = 40)

0.050

0.10

59.

What amount of KI (in moles) is required to prepare 250 cm³ of a 0.200 mol dm^–3 solution?

50.0

1.25

0.800

0.0500

60.

Which solution contains the greatest amount (in mol) of solute? (Mr KBr = 119)

10.0 cm³ of 0.500 mol dm^–3 KBr

20.0 cm³ of 0.400 mol dm^–3 KBr

30.0 cm³ of 0.300 mol dm^–3 KBr

40.0 cm³ of 0.200 mol dm^–3 KBr

100 %

mole and formulae

Total questions: 60

Worksheet time: 5hrs 0mins

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