Practicals Flashcards
1
Q
How to prepare pure, dry salt
A
- Measure acid into beaker
- Heat acid gently using BB
- Add small amounts of insoluble base with spatula until in excess when no more reacts
- Filter solution using filter paper and funnel to remove excess
- Evaporate solution using a water bath using 60 water bath until crystals form
- Pat crystals dry with paper towel
2
Q
Neutralisation/ Titration Practical
A
- Use pipette to measure 25cm3 of alkali into conical flask
- Stand conical flask onto white tile
- Fill burette with acid using a funnel
- Record initial reading of acid in burette
- Add small amount of indicator eg methyl orange/phenolphthalein into conical flask
- Slowly open burette tap while swirling conical flask
- Let acid drop by drop near endpoint
- Stop burette when a colour change thats permanent occurs in indicator
- Record final reading of acid in burette and calc titration
- Repeat until you have 2 concod=rdant results within 0.1cm3 of each other
3
Q
Electrolysis practical
A
- Add 50cm3 salt solution to a beaker
- Add lid and insert carbon rodes (electrodes) through holes, rods musnt touch each other
- Attach crocodile leads to electrodes, connect rods to DC terminals of a low voltage power supply
- Switch power supply on
- Record observations at each electrode
4
Q
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?
A
- chlorine
hydrogen
5
Q
Temperature changes practical
A
- Measure 25cm3 acid into polystyrene cup
- Stand the cup inside beaker - more stable
- Measure and record temp of acid
- Measure 5cm3 alkali and add into polystyrene cyp
- Put lif on cup and gently stir solution with thermometer though hole in lif
- When reading on thermometer stops changing, record temp
Repeat 4 and 5 to add further 5cm3 amounts of alkali into cup - total of 40cm3 - Repeat 1-7
- Calc mean max temp reached for each NaOH volumes
6
Q
Rates of Reaction practical
A
- Measure 50cm3 sodium thiosulfate solution into conical flask
- Put conical flask on the black cross
- Measure 10cm3 of dilute HCL
- Add acid to flask, same time = swirl flask gently and start stopclock
- Look down through top of flask, stop clock when you can no longer see cross and record time taken
- Repeat 1-6, 4 times, using diff conc of sodium thiosulfate and water
7
Q
Measuring the volume of a gas produced
A
- Measure 50cm3 of 2mol/dm3 HCL using one of the measuring cylinders. Pour the acid into the 100cm3 conical flask
- Set apparatus up =Delivery tube in conical flask and in water bath with upside down measuring cylinder held with a clamp
- Add a 3cm strip of Magnesium ribbon to flask and put bung back into the flask - Start stopclock
- Record colume of hydrogen gas given off every 10 seconds - stop when gas stops
- Repeat 1-4 with diff conc of HCL
8
Q
Chromatography
A
- Draw a horizontal pencil line 2cm above the bottom of the chromotography paper
- Mark pencil spots at equal intervals at 1cm between
- Use a small pipette to put ink on pencil spots
- Pour water in to beaker - less than 1cm
- Suspend paper in the beaker so bottom edge of the paper dips iinto the paper
- Wait for solvent to travel up the paper, remove paper and draw where the solvent reached
- Hang paper to dry
- Calc Rf value of each spot
9
Q
Flame test for metal ions
A
- Clean the nichrome wire by dipping it in dilute HCL
- Dip the nichrome wire into the unknown solution
- Hold the tip of the wire in a blue Bunsen Burner
10
Q
Positive results for flame tests for metal ions
A
- Potassium = lilac
- Calcium = orange-red
- Copper = green
- Sodium = yellow
- Lithium = crimson
11
Q
Sodium hydroxide test for metal ions
A
- Add a few drops of sodium hydroxide solution to unknown solution
- If there is a white precipitate, add more sodium hydroxide until in excess
12
Q
Positive result for sodium hydroxide test for metal ions
A
- Al 3+ = white precipitate that dissolves in excess NaOH
- Calcium 2+ = white precipitate doesnt dissolve in excess
- Magnesium 2+ = white precipitate doesnt dissolve in excess
- Copper II = blue precipitate
- Iron II = green precipitate
- Iron III = Brown precipitate
13
Q
Carbonate ion test
A
- Place a little limewater in a test tube
- Add a little HCL to unknown solution
- If there are bubbles, transfer gas produced to the limewater using a teat pippete or delivery tube
14
Q
Carbonate ion positive result
A
- Bubbles produced, limewater - cloudy
15
Q
Sulfate ion test + result
A
- Few drops of dilute HCL to unknown solution
- Add a little barium chloride solution
- White precipitate = present
16
Q
Halide ion test
A
- Few drops of dilute nitric acid to unknown solution
- Add a little silver nitrate solution
17
Q
Halide ion positive results
A
- Chloride = white precipitate
- Bromide = cream
- Iodide = yellow
18
Q
Water Purification
A
- Use universal indicator or a pH probe to test the ph of water
- Measure and record mass of empty evapporating basin
- Pour 10cm3 water into it and evaporate water using BB gently until water has evaporated
- Once basin is cooled to room temp, reweigh and record change in mass
- Calc mass of dissolved solids in water
19
Q
Purifying a sample of water by distillation
A
- Place water sample in a conical flask and set up the apparatus - flask on BB with delivery tube in test tube which is in water bath
- Heat water gently using BB until it boils, then reduce heat so water boils gently
- Collect around 1cm depth of water in the cooled test tube, then stop heating
- Analyse the water you have distilled with cobalt chloride paper
- Paper will go blue to pink when water is present
20
Q
Uncertainty equation
A
Range / 2
21
Q
A
