measuring the rate of reaction (Required Practical)

Question 1

what are the steps in the disappearing cross practical

Answer 1

1. use a measuring cylinder to put 10cm cubed sodium thiosulfate solution into a conical flask
2. place the conical flask onto a printed black cross
3. add 10cm cubed of hydrochloric acid into the conical flask
4. swirl the solution and start a stopwatch
5. look down at the solution and eventually will turn cloudy when the cross is fully disappeared then stop the stopwatch
6. carry out the experiment again using lower concentrations of sodium thiosulfate solution
7. repeat the experiment for each of the concentrations to calculate a mean value

Question 2

what is reproducability

Answer 2

measurements that can be repeated by another person,used different techniques or equipment can still get the same results

Question 3

what is one problem with the disappearing cross experiment and what is one way that you could try to solve this problem

Answer 3

people have different eyesight for some people the cross might be gone while for others it still may be visible

all students will use the same sized cross