Required Practicals

Question 1

what is the 1st step in the disappearing cross practical?

Answer 1

Use a measuring cylinder to put 10cm³ sodium thiosulfate solution into the conical flask

Question 2

what is the 2nd step in the disappearing cross practical?

Answer 2

Use the measuring cylinder to then add 40cm³ water. This dilutes the solution thiosulfate solution to a concentration of 8g/dm³

Question 3

what is the 3rd step in the disappearing cross practical?

Answer 3

Put the conical flask on the black cross

Question 4

what is the 4th step in the disappearing cross practical?

Answer 4

Put 10cm³ of dilute hydrochloric acid into the 10cm³ measuring cylinder

Question 5

what is the 5th step in the disappearing cross practical?

Answer 5

Put the acid into the flask. At the same time swirl the flask gently and start the stop-clock

Question 6

what is the 6th step in the disappearing cross practical?

Answer 6

Look down through the top of the flask. Stop the clock when you can no longer see the cross, stop the clock.
(Take care to avoid breathing in any sulfur dioxide fumes)

Question 7

what is the 7th step in the disappearing cross practical?

Answer 7

Repeat steps 1-5 4 times but in step 1