Factors Affecting Rate Of Reaction

Question 1

What is the practical for disappearing cross?

Answer 1

Add sodium thiosulfate into conical flask

Place conical flask on top of black cross

Add hcl into conical flask

Swirl and start stopwatch

Look down conical flask

Turns cloudy so stop stopwatch

Repeat for different concentrations of sodium thiosulfate

Question 2

What are problems with the black cross practical?

Answer 2

Different people have different eyesight which leads to different results

So we keep the size of cross the same

Question 3

What is the practical for volume of gas?

Answer 3

Add 50cm cubed of hcl into measuring cylinder

Add bung and delivery tube to conical flask

Fill delivery tube with water

Place measuring cylinder upside down in delivery tube

Add mg

Start stopwatch

Hcl gets trapped