Practicals

Question 1

How to prepare pure, dry salt

Answer 1

1. Measure acid into beaker
2. Heat acid gently using BB
3. Add small amounts of insoluble base with spatula until in excess when no more reacts
4. Filter solution using filter paper and funnel to remove excess
5. Evaporate solution using a water bath using 60 water bath until crystals form
6. Pat crystals dry with paper towel

Question 2

Neutralisation/ Titration Practical

Answer 2

1. Use pipette to measure 25cm3 of alkali into conical flask
2. Stand conical flask onto white tile
3. Fill burette with acid using a funnel
4. Record initial reading of acid in burette
5. Add small amount of indicator eg methyl orange/phenolphthalein into conical flask
6. Slowly open burette tap while swirling conical flask
7. Let acid drop by drop near endpoint
8. Stop burette when a colour change thats permanent occurs in indicator
9. Record final reading of acid in burette and calc titration
10. Repeat until you have 2 concod=rdant results within 0.1cm3 of each other

Question 3

Electrolysis practical

Answer 3

1. Add 50cm3 salt solution to a beaker
2. Add lid and insert carbon rodes (electrodes) through holes, rods musnt touch each other
3. Attach crocodile leads to electrodes, connect rods to DC terminals of a low voltage power supply
4. Switch power supply on
5. Record observations at each electrode

Question 4

Electrolysis practical:
1) What is present at the anode if dample blue litmus paper bleaches?
2) If a gas is produced at the cathode, what is the gas?

Answer 4

• chlorine
  hydrogen

Question 5

Temperature changes practical

Answer 5

1. Measure 25cm3 acid into polystyrene cup
2. Stand the cup inside beaker - more stable
3. Measure and record temp of acid
4. Measure 5cm3 alkali and add into polystyrene cyp
5. Put lif on cup and gently stir solution with thermometer though hole in lif
6. When reading on thermometer stops changing, record temp
   Repeat 4 and 5 to add further 5cm3 amounts of alkali into cup - total of 40cm3
7. Repeat 1-7
8. Calc mean max temp reached for each NaOH volumes

Question 6

Rates of Reaction practical

Answer 6

1. Measure 50cm3 sodium thiosulfate solution into conical flask
2. Put conical flask on the black cross
3. Measure 10cm3 of dilute HCL
4. Add acid to flask, same time = swirl flask gently and start stopclock
5. Look down through top of flask, stop clock when you can no longer see cross and record time taken
6. Repeat 1-6, 4 times, using diff conc of sodium thiosulfate and water