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4MA1/2F Jan 2020, Question 11: Direct Proportion in Real Life

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 2F (Foundation) · Calculator · 6 marks

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The question, in short

Use the signs + > = ∈ < to complete temperature comparisons, then use a table of boiling and freezing points of four elements to answer questions about lowest boiling point, largest temperature range, and cooling time for chlorine.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Part (ai) · 1 mark

Choose one of the five signs to place in the box so that the statement comparing 4 °C and 9 °C is true.

  1. 14 < 9

Answer<

Part (aii) · 1 mark

Choose one of the five signs to place in the box so that the statement comparing −3 °C and −8 °C is true.

  1. 1−3 > −8

Answer>

Part (b) · 1 mark

Using the table, identify which of the four elements has the lowest boiling point.

  1. 1Compare boiling points: −35, 357, −246, −183
  2. 2Lowest is −246
  3. 3Neon has boiling point −246°C

AnswerNeon

Part (c) · 1 mark

Using the table, find which element has the greatest temperature difference between its boiling point and freezing point.

  1. 1Chlorine: −35 − (−101) = 66
  2. 2Mercury: 357 − (−39) = 396
  3. 3Neon: −246 − (−249) = 3
  4. 4Oxygen: −183 − (−218) = 35
  5. 5Largest difference is 396
  6. 6Mercury

AnswerMercury

Part (d) · 2 marks

Chlorine cools from −35 °C to −101 °C at 2 minutes per 10 °C; work out the total time taken.

  1. 1Chlorine: boiling point −35 °C, freezing point −101 °C
  2. 2Drop = −35 − (−101) = 66 °C
  3. 3Time = 66 ÷ 10 × 2 = 13.2 minutes

Answer13.2

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