2020 P1 Q5 - Deducing Temperature and Boiling Point of Mixture

Let's take a look at 2020 A Levels H2 Chemistry Paper 1 Question 5.

2020 p1 q1 question

We are required to determine the initial temperature of the mixture and its boiling point.

Let's consider the process of mixing 2 liquids.

2020 p1 q1 process of mixing

CHCl3 and CHCl3 molecules are separated, while CH3COCH3 and CH3COCH3 molecules are separated.

Hence energy is required to overcome the attraction between these molecules.

On mixing CHCl3 and CH3COCH3 molecules, energy is released from the interactions formed between them.

It is stated that stronger intermolecular forces are formed between CHCl3 and CH3COCH3 molecules.

Therefore more energy is released than energy required and the process is exothermic.

This means heat is released during mixing which increases the temperature of the mixture to above 20oC.

Also, more energy is required to overcome the stronger attraction between the mixture, hence boiling point will be higher than that of CHCl3 at 61oC.

2020 p1 q1 deductions

We can now look at the options and figure out the answer.

Initial temperature of mixture is above 20oC while the boiling point of mixture is above 61oC.

2020 p1 q1 answer

Hence the answer to this question will be option A.

Topic: Intermolecular Forces, Physical Chemistry, A Level Chemistry, Singapore

Back to list of questions for 2020 A Level H2 Chemistry Paper 1.

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