Molecular and Empirical Formula

Molecular and Empirical Formula

Multiple Choice

What is the empirical formula of a sulfur oxide containing 4.62g of sulfur and 3.20g of oxygen?

• SO

• SO₂

• SO₃

• S₇O₂

Multiple Choice

What is the empirical formula of a compound containing 10.8g carbon, 2.4g hydrogen and 4.8g of oxygen?

• CH₄O

• C₂H₆O

• C₃H₈O

• C₄H₁₀O

Multiple Choice

What is the empirical formula of an oxide of nitrogen containing 63.61% by mass of nitrogen and 36.69% by mass of oxygen?

• NO

• NO₂

• N₂O

• N₂O₃

Multiple Choice

What is the empirical formula of a hydrocarbon containing 85.7% by mass of carbon and 14.3% by mass of hydrogen?

• CH

• CH₂

• C₂H₃

• C₂H₅

Multiple Choice

What is the molecular formula of aluminium chloride, containing 20.2% by mass of aluminium and 79.8% by mass of chlorine? M_r=267.0

• AlCl₃

• Al₂Cl₂

• Al₂Cl₄

• Al₂Cl₆

Multiple Choice

What is the molecular formula of a compound containing 25.6g of oxygen, 12.6g of sulfur and 0.4g of hydrogen? M_r=194.2

• HSO₄

• H₂SO₃

• H₂SO₄

• H₂S₂O₈

Multiple Choice

What is the correct definition of molecular formula?

• The formula giving the actual number of atoms of each element in a molecule.

• The formula giving the smallest whole-number of each element in a molecule.

• A pictorial representations of the arrangement of atoms in a molecule.

Multiple Choice

What is the correct definition of relative formula mass?

• Mass of a molecule relative to 1/12 the mass of carbon-12

• Mass of an element relative to 1/12 the mass of carbon-12

• Mass of formula unit of an ionic substance relative to 1/12 the mass of carbon-12

Multiple Choice

What is the correct definition of empirical formula?

• The formula giving the number of moles of each element in a substance

• The formula giving the smallest whole-number ratio of atoms of each element in a molecule

• The formula giving the actual number of atoms of each element in a molecule

Multiple Choice

What is the correct definition of a mole?

• The amount of substance containing as many molecules as there are atoms in 12g of ¹²C

• The amount of substance containing as many particles as there are atoms in 1g of ¹H

• The amount of substance containing as many particles as there are atoms in 12g of ¹²C

Multiple Choice

What is the correct definition of relative molecular mass?

• Mass of a molecule relative to 1/12 the mass of carbon-12.

• Mass of one mole of any substance

• Mass of a molecule relative to the mass of carbon-12

Multiple Choice

What is the relative molecular mass of sulfuric acid, H₂SO₄?

• 98.1

• 97.1

• 96.1

Multiple Choice

What is the relative molecular mass of lead nitrate, Pb(NO₃)₂?

• 662.4

• 331.2

• 269.2

Multiple Choice

Which is the correct equation for finding the number of moles in a sample of substance?

• no. of moles = mass/Mr

• no. moles = mass x Mr

• no. moles = Mr/mass

Multiple Choice

How many moles are there in 3.45g of sodium?

• 0.15

• 6.67

• 53.8

Multiple Choice

What is the mass of 5 moles of lead?

• 0.0241g

• 41.4g

• 1036g

Multiple Choice

What is the relative molecular mass of benzene given that 2.5 moles has a mass of 195g?

• 488

• 78.0

• 0.0128

Multiple Choice

What is the molecular formula of an organic compound that contains 3.51g of carbon and 0.29g of hydrogen, and which has Mr of 78.

• C₃H₆

• C₆H₆

• C₅H₁₈