Practicals Flashcards
Describe a method to make pure, dry crystals of magnesium sulfate from a metal oxide and a dilute acid
- Add sulfuric acid to a beaker
- Warm sulfuric acid
- Add metal oxide and stir
- Continue adding metal oxide until it is in excess
- Filter out excess metal oxide using filter paper and a funnel
- Heat solution in an evaporating basin to crystallisation point
- Leave in a cool place to crystallise
- Pat dry with filter paper
Plan an experiment to investigate temperature change
- Place a polystyrene cup in a beaker
- Use a measuring cylinder to put 25cm³ of dilute hydrochloric acid into the cup
- Place a lid on the cup and make a hole in it
- Place the thermometer into the hole and record the starting temperature
- Use the measuring cylinder to put 5cm³ of sodium hydroxide into the cup
- Swirl the solution using the thermometer
- Record the highest temperature reached
- Repeat experiment several times, increasing volume of sodium hydroxide by 5cm³ each time until it reaches 40cm³
Give one independent variable in the temperature change experiment
Volume of sodium hydroxide solution
Give one control variable in the temperature change experiment
Volume of hydrochloric acid
Give one dependent variable in the temperature change experiment
Temperature change
Plan an experiment to investigate how the concentration of a reactant affects the rate of reaction (disappearing cross experiment)
- Use a measuring cylinder to put 10 cm³ of sodium thiosulfate into a conical flask
- Place the conical flask onto a printed black cross
- Add 10cm³ of hydrochloric acid to the conical flask
- Swirl solution and start a stopwatch
- Look down through the top of the flask
- Stop the clock when the cross can no longer be seen
- Repeat experiment using different concentrations of sodium thiosulfate
Plan an experiment to investigate how the concentration of a reactant affects the rate of reaction (volume of gas released)
- Use a measuring cylinder to put 50cm³ of hydrochloric acid into a conical flask
- Connect the bung and delivery tube to the flask
- Connect the tube to the gas syringe/upside down measuring cylinder
- Add a 3cm piece of magnesium ribbon to the flask
- Start a stopwatch
- Record the volume of hydrogen gas collected every 10 seconds
- Continue until no more hydrogen is given off
- Repeat experiment with different concentrations of hydrochloric acid
Write a method for chromatography
- Draw pencil start line on chromatography paper
- Place spot of [mixture] on start line
- Place [solvent] in a beaker
- Place chromatography paper in solvent
–> [solvent] should be below start line - Use a lid
- Wait for solvent to travel up chromatography paper
- Mark solvent front
- Dry the chromatography paper
Write a method for a flame test
- Clean wire (using HCl)
- Dip wire into unknown compound
- Place in roaring (blue) flame
- Observe the colour
Name the 5 metal compounds that can be detected through flame tests
- Lithium
- Sodium
- Potassium
- Calcium
- Copper
(LSPCC)
Name the colour produced from a positive lithium flame test
Crimson
Name the colour produced from a positive sodium flame test
Yellow
Name the colour produced from a positive potassium flame test
Lilac
Name the colour produced from a positive calcium flame test
Orange-red
Name the colour produced from a positive copper flame test
Green