Grade 12 Physical Sciences · Chemical Change

Sketch a Maxwell-Boltzmann curve

Sketch or read the curve of how many particles have each kinetic energy, and show how it shifts at a higher temperature.

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Maxwell Boltzmann Distribution Curve grade 12Kevinmathscience

Rate of Reaction Maxwell-Boltzmann distribution curve Grade 12 ChemistryMiss Martins Maths and Science

Effect of Temperature and Catalysts on Rate and Maxwell-Boltzmann Distributions | AP Chem - KineticsSiebert Science

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Question 5.5 · November 2023 · Paper 2 · National (DBE) · 4 marks

The reaction between EXCESS dilute hydrochloric acid and sodium thiosulphate is used to investigate factors that influence reaction rate.

Na_{2} S_{2} O_{3} (aq) + 2 HCl(aq) \to 2 NaCl(aq) + S(s) + H_{2} O (ℓ) + SO_{2} (g)

The concentration of HCl(aq) used is

1

mol·dm

^{- 3}

. The same volume of HCl(aq) is used in each run.

The time taken for the cross on the paper under the flask to become invisible is measured.

The table below summarises the reaction conditions and results of the experiment. Diagram for this question

Another investigation is performed at different temperatures.

5.5 Sketch the Maxwell-Boltzmann distribution curve for the reaction at

20

°C. Label this curve as A. On the same set of axis, draw the curve that will be obtained at

35

°C and label it as B.(4)

Work it out on paper first. Then mark yourself with the official memo, one tick at a time.

More past paper questions: sketch a maxwell-boltzmann curve

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3. Question 5.3.5 · November 2025 · Paper 2 · National (DBE) · 2 marks
5.3 The reaction between sulphur dioxide, $SO_{2}$ (g), and oxygen, $O_{2}$ (g), takes place in a sealed container according to the balanced equation below.

$2 SO_{2} (g) + O_{2} (g) ⇌ 2 SO_{3} (g)$ $Δ H = - 196$ kJ·mol $^{- 1}$

Answer the questions that follow.
5.3.5 Redraw the above graph in the ANSWER BOOK. On the same set of axes, draw the curve that will now be obtained. Label this as curve Y.(2)
Show the memo (2 ticks)Memo
1. ✓
  Both curves start at origin, same shape, peaks at same EkBoth curves start at the origin and have the correct shape, with their peaks at the same kinetic energy.
  1 mark · Sketch a Maxwell-Boltzmann curve
2. ✓
  Peak of Y higher than X at the same EkPeak of curve Y must be higher than curve X with peaks at the same $E_{k}$ .
  1 mark · Sketch a Maxwell-Boltzmann curve
4. Question 5.4.1 · May/June 2023 · Paper 2 · National (DBE) · 2 marks
Consider the following decomposition reaction that takes place in a sealed $2$ dm $^{3}$ container:

$2 N_{2} O_{5} (g) \to 4 NO_{2} (g) + O_{2} (g)$

The graph below shows how the concentrations of $N_{2} O_{5}$ (g) and $NO_{2}$ (g) change with time.
5.4 The Maxwell-Boltzmann distribution curve for the $N_{2} O_{5}$ (g) initially present in the container is shown below.

The initial concentration of the $N_{2} O_{5}$ (g) is now INCREASED.

Answer the questions that follow.
5.4.1 Redraw the distribution curve above in the ANSWER BOOK and label this curve as P.

On the same set of axes, sketch the curve that will be obtained for the higher concentration of $N_{2} O_{5}$ (g). Label this curve as Q.(2)
Show the memo (2 ticks)Memo
1. ✓
  Curve Q above P, same shape, peaks correspondCurve Q lies above the given curve P, has the same shape as P, and its peak is at the same kinetic energy as the peak of P.
  1 mark · Sketch a Maxwell-Boltzmann curve
2. ✓
  Starts at origin and does not cross PCurve Q starts at the origin and does not cross curve P.
  1 mark · Sketch a Maxwell-Boltzmann curve
5. Question 5.5 · May/June 2022 · Paper 2 · National (DBE) · 2 marks
Learners use the reaction of $MgCO_{3}$ (s) with EXCESS dilute HC $ℓ$ (aq) to investigate the relationship between temperature and the rate of a chemical reaction.

The balanced equation for the reaction is:

$MgCO_{3} (s) + 2 HC ℓ (aq) \to MgC ℓ_{2} (aq) + CO_{2} (g) + H_{2} O (ℓ)$

The results obtained are represented in the graph below.
The graph below represents the Maxwell-Boltzmann distribution curve for $CO_{2}$ (g) at $40$ °C.
5.5 Redraw the graph above in the ANSWER BOOK. Clearly label the curve as A.

On the same set of axes, sketch the curve that will be obtained for the $CO_{2}$ (g) at $20$ °C. Label this curve as B.(2)
Show the memo (2 ticks)Memo
1. ✓
  Higher peak to the leftCurve B has a higher peak to the left of curve A.
  1 mark · Sketch a Maxwell-Boltzmann curve
2. ✓
  Below A beyond the peakCurve B is below curve A beyond the peak of curve A.
  1 mark · Sketch a Maxwell-Boltzmann curve
6. Question 5.2.1 · November 2024 · Paper 2 · National (DBE) · 1 mark
5.2 Curve X is the Maxwell Boltzmann distribution curve for a reaction under a set of reaction conditions. A change was made to one of the reaction conditions to obtain curve Y.

Answer the questions that follow.
5.2.1 What change was made to obtain curve Y?(1)
Show the memo (1 tick)Memo
1. ✓
  Change madeAn increase in temperature.
  1 mark · Sketch a Maxwell-Boltzmann curve

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