Chemistry 9701/21 — October/November 2011
Cambridge AS Level · AS Level Structured Questions · worked solutions for every part, with the mark scheme
Topics Carboxylic Acids and Derivatives · Carbonyl Compounds · Hydrocarbons · Hydroxy Compounds · Atoms, Molecules and Stoichiometry · States of Matter · +6 more
Compound A is an organic compound which contains carbon, hydrogen and oxygen.
When 0.240 g of the vapour of A is slowly passed over a large quantity of heated copper(II) oxide, CuO, the organic compound A is completely oxidised to carbon dioxide and water. Copper is the only other product of the reaction.
The products are collected and it is found that 0.352 g of CO₂ and 0.144 g of H₂O are formed.
In this section, give your answers to three decimal places.
Calculate the mass of carbon present in 0.352 g of CO₂.
Use this value to calculate the amount, in moles, of carbon atoms present in 0.240 g of A.
Calculate the mass of hydrogen present in 0.144 g of H₂O.
Use this value to calculate the amount, in moles, of hydrogen atoms present in 0.240 g of A.
Use your answers to calculate the mass of oxygen present in 0.240 g of A.
Use this value to calculate the amount, in moles, of oxygen atoms present in 0.240 g of A.
Use your answers to (a) to calculate the empirical formula of A.
When a 0.148 g sample of A was vapourised at 60 °C, the vapour occupied a volume of 67.7 cm³ at a pressure of 101 kPa.
Use the general gas equation to calculate of A.
= ......................
Hence calculate the molecular formula of A.
Compound A is a liquid which does not react with 2,4-dinitrophenylhydrazine reagent or with aqueous bromine.
Suggest two structural formulae for A.
Compound A contains only carbon, hydrogen and oxygen.
Explain how the information on the opposite page about the reaction of A with CuO confirms this statement.
The rest of this paper
4 more questions- Q2Atomic Structure · Chemical Periodicity15M
- Q3Chemical Energetics · Carboxylic Acids and Derivatives11M
- Q4Hydrocarbons · Hydroxy Compounds · Carboxylic Acids and Derivatives7M
- Q5Introduction to Organic Chemistry · Hydroxy Compounds · Carbonyl Compounds · Organic Synthesis · Nitrogen Compounds14M