Year 12 Chemistry Chapter 11

A student wants to use a physical property to distinguish between two alcohols, octan-1-ol and propan-1-ol. Both alcohols are colourless liquids at standard laboratory conditions (SLC).

The student should use

• density because propan-1-ol has a much higher density than octan-1-ol.

• boiling point because octan-1-ol has a higher boiling point than propan-1-ol.

• electrical conductivity because octan-1-ol has a higher conductivity than propan-1-ol.

• spectroscopy because it is not possible to distinguish between the alcohols using their physical properties.

Which one of the following statements about flashpoints is correct?

• The flashpoint of butane is lower than 25 °C.

• As a flashpoint increases, the viscosity decreases.

• The flashpoint of a compound is higher than its boiling point.

• The flashpoint of butane is greater than the flashpoint of butan-1-ol.

The table shown to the left provides information about three organic compounds, X, Y and Z.

Which one of the following is the best estimate for the boiling point of Compound Z?

• 31 °C

• 101 °C

• 114 °C

• 156 °C

A synthesis experiment was conducted in which 4.50 g of CH₃CH₂CH₂COOH (M = 88 g mol^–1) was heated with an excess of CH₃CH₂CH₂OH (M = 60 g mol^–1) in the presence of a sulfuric acid catalyst. The mass of the ester (M = 130 g mol^–1) produced was 5.32 g.

What is the name of the ester formed in the reaction?

• 1-butyl butanoate

• 1-propyl butanoate

• 1-butyl propanoate

• 1-propyl propanoate

A synthesis experiment was conducted in which 4.50 g of CH₃CH₂CH₂COOH (M = 88 g mol^–1) was heated with an excess of CH₃CH₂CH₂OH (M = 60 g mol^–1) in the presence of a sulfuric acid catalyst. The mass of the ester (M = 130 g mol^–1) produced was 5.32 g.

The per cent atom economy for the reaction is closest to

• 70%

• 75%

• 80%

• 85%

A synthesis experiment was conducted in which 4.50 g of CH₃CH₂CH₂COOH (M = 88 g mol^–1) was heated with an excess of CH₃CH₂CH₂OH (M = 60 g mol^–1) in the presence of a sulfuric acid catalyst. The mass of the ester (M = 130 g mol^–1) produced was 5.32 g.

The percentage yield of the ester in the synthesis is closest to

• 70%

• 75%

• 80%

• 85%

The structural formula of a particular compound is shown to the left.

What mass of bromine molecules would react with 0.150 mole of this compound?

• 12.0 g

• 24.0 g

• 36.0 g

• 47.9 g

Equal volumes of liquid CH₃CH₂CH₂CH₂COOH and liquid CH₃CH₂CH₂OH were mixed and heated in the presence of a small volume of concentrated sulfuric acid.

Which one of the following could be a product of the reaction?

• propyl butanoate

• butyl propanoate

• pentyl propanoate

• propyl pentanoate

Equal volumes of liquid CH₃CH₂CH₂CH₂COOH and liquid CH₃CH₂CH₂OH were mixed and heated in the presence of a small volume of concentrated sulfuric acid.

What is the major role of the sulfuric acid in the reaction?

• donating protons

• acting as an oxidant

• catalysing the reaction

• being a dehydrating agent

Ethoxyethane, C₂H₅OC₂H₅, is commonly used as a solvent in the purification of compounds. The boiling point of

C₂H₅OC₂H₅ is 36 °C.

The safety data sheet for C₂H₅OC₂H₅ states: ‘Extremely flammable. Keep away from sources of ignition.’

During the purification process, a compound is dissolved in C₂H₅OC₂H₅ by heating it for an extended period of time.

This is done using glassware that is open to the atmosphere.

This step in the purification process should be carried out using a

• water bath in a fume cupboard.

• water bath on a laboratory bench.

• Bunsen burner in a fume cupboard.

• Bunsen burner on a laboratory bench.