RP5

Question 1

disappearing cross

Answer 1

1. use a mc to put 10cm3 of sts s into a conical flask
2. place conical flask onto a black cross
3. add 10cm3 of hcl into conical flask
4. swirl solution + star =t stopwatch
5. look down through top of cf - will turn cloudy after certain time
6. stop clock when cross no longer visiblel
7. carry out experiment again using ower concentrations of sth s
8. repeat whole experiment and calc mean for each concentration of sth s

Question 2

volume of gas produced by a reaction

Answer 2

1. use mc to put 50cm3 of hcl into a cf
2. attatch bung + gas syringe to cf
3. add a 3cm strip of mg to hcl and start stopwatch immediately
4. every 10s measure volume of hydrogen gas in gas syringe + continue until no more is given off
5. repeat experiment with different cobetrations of hcl
6. repeat whole experiment = calc mean values for each concentration of hcl