Question 137 – Rates of reaction - Edexcel Chemistry Questions

An aqueous reaction between sodium thiosulfate (solution A) and dilute hydrochloric acid (solution B) produces a cloudy suspension of yellow sulfur.

To investigate how different factors affect the kinetics of this reaction, a student placed a conical flask containing the reaction mixture on top of a sheet of paper marked with a bold black cross 'X'. The student measured the time taken for the sulfur precipitate to completely obscure the cross when viewed from directly above.

Disappearing cross experiment

The student's results are recorded in the table below:

Trial	Concentration of sodium thiosulfate in $mol/dm3\text{mol/dm}^3$	Temperature in $∘C^{\circ}\text{C}$	Time taken for cross to disappear in $s\text{s}$
1	0.05	20	180
2	0.05	40	45
3	0.20	40	11

Use the results in the table to explain, in terms of collision theory, the effect of:

changing the temperature, and
changing the concentration of sodium thiosulfate, on the rate of this reaction.

An aqueous reaction between sodium thiosulfate (solution A) and dilute hydrochloric acid (solution B) produces a cloudy suspension of yellow sulfur.

Disappearing cross experiment

The student's results are recorded in the table below:

Trial	Concentration of sodium thiosulfate in $mol/dm3\text{mol/dm}^3$	Temperature in $∘C^{\circ}\text{C}$	Time taken for cross to disappear in $s\text{s}$
1	0.05	20	180
2	0.05	40	45
3	0.20	40	11

Use the results in the table to explain, in terms of collision theory, the effect of:

changing the temperature, and
changing the concentration of sodium thiosulfate, on the rate of this reaction.

Rates of reaction

Question 37

Rates of reaction

Question 37

Rates of reaction

Question 37

Rates of reaction Questions

Rates of reaction

Question 37

Rates of reaction Questions