Required Practicals for AQA A Level Chemistry INCOMPLETE

Making up a standard solution
Stage 1: transferring a ❌ mass of the solid
• Weigh the solid into a weighing boat recording the mass (to appropriate precision).
• Transfer the solid to a ❌.
• Re-weigh the weighing boat and record the ❌ in mass.
Stage 2: dissolving the solid in distilled water
• Add the ❌ distilled water to the beaker to dissolve.
• Stir the beaker with the ❌ until the solid has dissolved.
Stage 3: rinsing all glassware and making up the solution
• Transfer the solution to a ❌ using a funnel.
• Rinse all used glassware into the volumetric flask (glass rod, beaker and ❌).
• Add ❌ water up to the ❌ (on the volumetric flask).
• ❌ the flask several times.

Carrying out an acid-base titration
Stage 1: Preparing the conical flask
• Using a ❌, transfer the desired amount of the acidic solution into the conical flask.
• Add several drops of an appropriate ❌ to the conical flask.
• Rinse any solution on the sides of the flask into the flask with ❌.
Stage 2: preparing the burette
• Fill the burette up with the basic solution using a ❌.
• Run the solution through the jet, ensuring that there are no ❌ present.
• Remove the funnel from the burette.
Stage 3: performing the titration
• Place the conical flask on a ❌ beneath the burette.
• Record the starting volume of the burette.
• Titrate the solution, swirling the ❌ until a ❌ colour change is observed.
• Record the end volume in the ❌ and calculate the titre.
• Repeat until ❌ results (titre values within 0.1 cm³ of each other) are achieved and calculate a mean titre (never include ❌ values).

Experimentally finding the enthalpy change of combustion
Stage 1: preparing the chemicals
• Add the fuel to the ❌ and record the initial mass.
• Add a known quantity of water to the ❌ and clamp in position above the spirit burner.
• Use thermometer to measure the initial temperature of the ❌.
Stage 2: carrying out the experiment
• Use the spirit burner to heat water in the calorimeter to roughly (40ᵒC) and record the ❌.
• Reweigh the spirit burner and calculate the ❌ of the fuel.
Stage 3: interpreting the results
• Calculate the energy released (❌) using the equation q = mcΔT where q = ❌; m = mass of water heated; c = ❌ (4.18); ΔT = change in temperature.
• Calculate the enthalpy change (❌) using the equation ΔH = q / (moles of fuel).
• Convert into ❌ by dividing your answer by 1000.

Experimentally finding the enthalpy change of a reaction, accounting for heat loss
Add a (5.00g) sample of solid to (50g) of ❌ and start the stop watch.
Record the ❌ of the solution every subsequent minute for approximately 5 minutes.
Plot a graph of temperature (y-axis) versus time (x-axis).
❌ back to the time of ❌ (T=0s) to establish the ❌ temperature change.
Calculate ΔH in kJ mol-1 using the equation: ΔH = (m × c × ∆T)/(n ×1000 )

Investigate how the rate of reaction changes with temperature
1. Set a ❌ to 20ᵒC.
2. Accurately measure out 20cm³ of 1.0 mol dm⁻³ hydrochloric acid and pour into a ❌.
3. Allow the solution of hydrochloric acid to reach the ❌ of the water bath.
4. ❌ weigh out 1.0g of magnesium ribbon.
5. Place the magnesium into the conical flask, immediately attaching the ❌ and starting a timer.
6. Record the ❌ of gas evolved in the first 20 seconds.
7. Repeat steps 1 – 6 for a ❌ of temperatures (30ᵒC – 60ᵒC).
8. Plot a graph of temperature (❌) versus initial rate (cm³/20s) (❌).