Stoichiometry and the Mole

A mole of a substance is defined as
1. the amount of substance that contains as many particles as there are in 12 grams of the C-12 isotope.
2. the amount of substance contained in 12 grams of carbon.
3. the amount of substance in 16 grams of oxygen.
4. the number of atoms in 12 grams of carbon.
The sum of the relative atomic masses of all the atoms in a molecule is known as
1. its relative molecular mass
2. the Avogadro number
3. a mole
4. its molar volume
One mole of a substance contains
1. 6.0 x 10²³ particles of that substance.
2. 6.2 x 10³² particles of that substance.
3. 6.23 x 10 particles of that substance.
4. 10 x 6²³ particles of that substance.
For the chemical reaction shown, how many moles of NH₃ are formed when 2 moles of N₂ react with 8 moles of H₂?
N₂ + 3H₂ ⇌ 2NH₃
1. 4 moles
2. 1 mole
3. 3 moles
4. 2 moles
How many atoms are there in 2.5 moles of Gold (Au)?
1. 1.5 x 10²⁴
2. 1.5 x 10²³
3. 3.0 x 10²³
4. 3.0 x 10²⁴
There are 3 x 10²³ molecules in a sample of hydrogen (H₂) gas.
How many moles of H₂ are there in this sample?
1. 0.5 mole
2. 3 moles
3. 5 moles
4. 0.3 mole
How many atoms are there in 1.5 moles of sulfur dioxide (SO₂)?
1. 2.7 x 10²⁴
2. 9.0 x 10²³
3. 9.0 x 10²⁴
4. 2.7 x 10²³
If the molar volume of a gas at STP is 22.4 litres, how many moles are there in 112 litres of hydrogen gas?
1. 5 moles
2. 10 moles
3. 2 moles
4. 20 moles
The average mass of a molecule of a substance relative to one-twelfth the mass of a carbon-12 atom is known as
1. the relative molecular mass.
2. the relative atomic mass.
3. a mole of a that substance.
4. the molar mass of that substance.
The mass in grams of a mole of a substance is known as
1. molar mass.
2. molar volume.
3. relative molecular mass.
4. a mole.
The relative atomic mass of hydrogen is 1, and that of oxygen is 16, and that of sulfur is 32. What is the relative molecular mass of sulfuric acid (H₂SO₄)?
1. 98
2. 49
3. 66
4. 96
There are 22,400 cm³ in a mole of any gas at STP. How many cm³ are there in 0.05 mole of a gas at STP?
1. 1,120 cm³
2. 112 cm³
3. 44,800 cm³
4. 448 cm³
The relative atomic masses of sodium, oxygen and hydrogen are 23, 16 and 1 respectively. How many grams are there in 0.5 mole of sodium hydroxide (NaOH)?
1. 20 grams
2. 40 grams
3. 38 grams
4. 17 grams.
Which one of the following instruments is used for determining the relative molecular mass of a substance?
1. Mass spectrometer
2. Hofmann voltameter
3. Cathode ray tube
4. Geiger-Muller tube
The molar mass of a substance is defined as
1. the mass in grams of 1 mole of that substance.
2. the mass in grams of 1 litre of that substance.
3. the number of moles in 1 litre of that substance.
4. the number of moles in 1 kilogram of that substance.
If Avogadro's Number is 6 x 10²³, then how many atoms are there in 2.5 moles of hydrogen gas (H₂)?
1. 3.0 x 10²⁴
2. 3.0 x 10²³
3. 1.5 x 10²³
4. 1.5 x 10²⁴
If the molar volume of methane (CH₄) is 22,400 cm³ and its molar mass is 16 grams, then how many grams of methane are there in 112 cm³ of methane gas?
1. 0.08 gram
2. 0.8 gram
3. 1400 grams
4. 20 grams
What will the mass of 5,600 cm³ of nitrogen gas (N₂) be at STP? {M_r(N₂) = 28 and molar volume at stp = 22,400 cm³}
1. 7 grams
2. 14 grams
3. 28 grams
4. 112 grams
What is the amount of atoms, in moles, in 88 g of carbon dioxide?
1. 6
2. 1.024 ×10²⁴
3. 6.02 ×10²³
4. 1
The isotopic abundances for an element R, are

What is the relative atomic mass of element R?
1. 28.8
2. 28.2
3. 28.5
4. 14
How many molecules are present in a 9.0 g sample of water?
1. 3.0 ×10²³
2. 6.0 ×10²³
3. 1.0
4. 0.5
What is the coefficient for oxygen when this equation is balanced using the lowest whole number?
C₄H₁₀ → CO + H₂O
1. 9
2. 4
3. 5
4. 13
What is the maximum mass of iron that can be produced from the reduction of 80 tonnes of iron(III) oxide (Mr = 160) , based on the following equation?
Fe₂O₃ + 3CO → 2Fe + 3CO₂
1. 56 tonnes
2. 28 tonnes
3. 84 tonnes
4. 112 tonnes
Which expression gives the number of moles of a substance, if the mass is given in grams?
1. Mass ÷ Molar mass
2. Molar mass ÷ Mass
3. 1 ÷ Molar mass
4. Mass × Molar mass
What is the total number of atoms in 0.20 mol of propanone, CH₃COCH₃?
1. 1.2 ×10²⁴
2. 6.0 ×10²³
3. 1.2 ×10²²
4. 6.0 ×10²⁴
Ethyne, C₂H₂, reacts with oxygen according to the equation below. What volume of oxygen (in dm³)
reacts with 0.40 dm³ of C₂H₂?
2C₂H₂ + 5O₂ → 4CO₂ = 2H₂O
1. 1.0
2. 0.80
3. 0.40
4. 2.0
When the equation below is balanced for 1 mol of C₃H₄, what is the coefficient for O₂?
C₃H₄ + _O₂ → _CO₂ + _H₂O
1. 4
2. 2
3. 3
4. 5
The equation for the complete combustion of butane is
2C₄H₁₀ + 13O₂ → 8CO₂ +10H₂O
How many moles of of carbon dioxide are formed by the complete combustion of three moles of butane?
1. 12
2. 4
3. 8
4. 24
A reaction occurring in the extraction of lead from its ore can be represented by this unbalanced equation:
__ PbS + __O₂ → __ PbO+ __ SO₂
When the equation is balanced using the smallest possible whole numbers, what is the coefficient of O₂
1. 3
2. 2
3. 1
4. 4
The equation for a reaction occurring in the synthesis of methanol is
CO₂ + 3H₂ → CH₃OH + H₂O
What is the maximum amount of methanol that can be formed from 2 mol of carbon dioxide and 3 mol of hydrogen?
1. 1 mol
2. 2 mol
3. 3 mol
4. 5 mol
Calcium carbonate decomposes on heating as shown below:
CaCO₃ → CaO + CO₂
1. 25%
2. 7%
3. 50%
4. 75%
Sodium reacts with water as shown below:
_Na + _H₂O → _NaOH + H₂
What is the total of all the coefficients when the equation is balanced using the smallest possible whole numbers?
1. 7
2. 6
3. 4
4. 3
Consider the following reaction:
2C₄H₁₀ + 13O₂ → 8CO₂ (g)+10H₂O
How many moles CO₂ of are produced by the complete combustion of 58 g of butane (C₄H₁₀)?
1. 4
2. 8
3. 12
4. 16
What volume of 0.50 mol dm⁻³ HCl(aq) is required to react completely with 10.0 g of calcium carbonate according to the following equation?
CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂
1. 400 cm³
2. 200 cm³
3. 300 cm³
4. 100 cm³
How many hydrogen atoms are there in one mole of ethanol, C₂H₅OH?
1. 3.6 ×10²⁴
2. 1.0 ×10²³
3. 5
4. 6
The percentage by mass of the elements in a certain compound is
C = 72%, H =12%, O =16%
What is the mole ratio of C:H:O in the empirical formula of this compound?Relative atomic masses:
H = 1, C = 12, O = 16
1. 6:12:1
2. 1:12:1
3. 1:12:6
4. 6:1:12
What is the coefficient for O₂ when the equation below is balanced?
C₃H₈ + __O₂ → __CO₂ + __H₂O
1. 5
2. 2
3. 3
4. 7
How many oxygen atoms are present in 0.0500 mol carbon dioxide?
1. 6.02×10²²
2. 3.01×10²²
3. 6.02×10²³
4. 1.20×10²⁴
A certain sample of the element X contains 60% of X-69 and 40% of X-71 isotopes.
What is the relative atomic mass of this element?
1. 69.8
2. 69.2
3. 70.0
4. 70.2
How many litres of nitrogen dioxide gas could theoretically be obtained in the reaction of 1 litre of nitrogen monoxide gas with 2 litres of oxygen gas?
(All volumes are measured under the same conditions of temperature and pressure.)
2NO_(g) + O_2(g) → 2NO_2(g)
1. 1
2. 2
3. 3
4. 4
Calcium carbonate reacts with nitric acid as follows:
CaCO_3(s) + 2HNO_3(aq) → Ca(NO₃)_2(aq) + H₂O_(l) + CO_2(g)
0·05 mol of calcium carbonate was added to a solution containing 0·08 mol of nitric acid.
Which of the following statements is true?
1. Calcium carbonate is in excess by 0·01 mol.
2. Nitric acid is in excess by 0·03 mol.
3. 0·05 mol of carbon dioxide is produced.
4. 0·08 mol of calcium nitrate is produced.
A hydrocarbon contains 90 % by mass of carbon.
What is its empirical formula?
Relative atomic masses:
H = 1, C = 12
1. C₃H₄
2. CH₂
3. C₇H₁₀
4. C₉H₁₀
Lithium hydroxide reacts with carbon dioxide as follows:
2LiOH + CO₂ → Li₂CO₃ + H₂O
What mass (in grams) of lithium hydroxide is needed to react with 11 g of carbon dioxide?
Relative atomic masses:
H = 1, Li = 7, C = 12, O = 16
1. 12
2. 6
3. 24
4. 48
A given number of moles of a gas at a constant temperature will
1. increase its volume if the pressure decreases.
2. increase its volume if the pressure increases.
3. decrease its volume if the pressure decreases.
4. have a constant volume if the pressure changes.
Which of the following is not conserved during a chemical reaction?
1. The number of molecules
2. The mass
3. The number of electrons
4. The number of atoms

Stoichiometry and the Mole

Multiple Choice Quiz