3.1.2.4 Empirical + molecular formula

What is the empirical formula of an oxide of nitrogen that contains 26% nitrogen by mass?

• NO₂

• N₂O₃

• N₂O₅

• N₄O₅

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.

What is the empirical formula of J?

• C₄HNO₂

• CH₂N₂O

• C₂HNO₂

• CHNO

What is the empirical formula of 4-hydroxypent-2-ene?

• C₅H₁₂O

• C₅H₁₀O

• CH₂O

• C₅H₉OH

An organic compound is found to contain 40.0% carbon, 6.7% hydrogen and 53.3% oxygen.

Which of the following compounds could this be?

• Ethanol

• Ethanoic acid

• Methanol

• Methanoic acid

Propanoic acid reacts with methanol in the presence of a small amount of concentrated sulphuric acid. The empirical formula of the ester formed is

• CH₂O

• C₂H₆O₂

• C₂H₄O₂

• C₂H₄O

An alkane contains 30 hydrogen atoms per molecule. Its empirical formula is

• C₆H₁₅

• C₇H₁₅

• C₁₄H₃₀

• C₁₅H₃₀

CH₂O is the empirical formula of

• methanol

• methyl methanoate

• ethane-1,2-diol

• butanal

When TiCI₄ is reduced with hydrogen under certain conditions, a new compound is produced which contains 68.9% chlorine by mass. Which one of the following could be the formula of the new compound?

• TiH₂Cl₂

• TiCl

• TiCl₂

• TiCl₃