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Required Practicals for AQA A Level Chemistry INCOMPLETE

Leah Firmstone 15 preguntas

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Preguntas del test (15)

  1. 1Making up a standard solution
    Stage 1: transferring a [blank_start]known[blank_end] mass of the solid
    • Weigh the solid into a weighing boat recording the mass (to appropriate precision).
    • Transfer the solid to a [blank_start]beaker[blank_end].
    • Re-weigh the weighing boat and record the [blank_start]difference[blank_end] in mass.
    Stage 2: dissolving the solid in distilled water
    • Add the [blank_start]minimum[blank_end] distilled water to the beaker to dissolve.
    • Stir the beaker with the [blank_start]glass rod[blank_end] until the solid has dissolved.
    Stage 3: rinsing all glassware and making up the solution
    • Transfer the solution to a [blank_start]volumetric flask[blank_end] using a funnel.
    • Rinse all used glassware into the volumetric flask (glass rod, beaker and [blank_start]funnel[blank_end]).
    • Add [blank_start]distilled[blank_end] water up to the [blank_start]graduation line[blank_end] (on the volumetric flask).
    • [blank_start]Invert[blank_end] the flask several times.
    1. Abeaker
    2. Bdifference
    3. Cknown
    4. Dminimum
    5. Eglass rod
    6. Fvolumetric flask
    7. Gdistilled
    8. Hgraduation line
    9. Ifunnel
    10. JInvert
  2. 2Which of the following should you NOT do when making up a standard solution?
    1. AWeigh the weighing boat with the solid in it, and then again after the solid has been transferred to a beaker.
    2. BInvert the volumetric flask before using the solution.
    3. CAdd distilled water to just above the graduation line, then use a dropping pipette to remove the extra.
  3. 3Any glassware that has been in contact with the solution should be rinsed into the volumetric flask when making up a standard solution.
    1. AVerdadero
    2. BFalso
  4. 4Carrying out an acid-base titration
    Stage 1: Preparing the conical flask
    • Using a [blank_start]glass pipette[blank_end], transfer the desired amount of the acidic solution into the conical flask.
    • Add several drops of an appropriate [blank_start]indicator[blank_end] to the conical flask.
    • Rinse any solution on the sides of the flask into the flask with [blank_start]distilled water[blank_end].
    Stage 2: preparing the burette
    • Fill the burette up with the basic solution using a [blank_start]funnel[blank_end].
    • Run the solution through the jet, ensuring that there are no [blank_start]air bubbles[blank_end] present.
    • Remove the funnel from the burette.
    Stage 3: performing the titration
    • Place the conical flask on a [blank_start]white tile[blank_end] beneath the burette.
    • Record the starting volume of the burette.
    • Titrate the solution, swirling the [blank_start]conical flask[blank_end] until a [blank_start]permanent[blank_end] colour change is observed.
    • Record the end volume in the [blank_start]burette[blank_end] and calculate the titre.
    • Repeat until [blank_start]concordant[blank_end] results (titre values within 0.1 cm³ of each other) are achieved and calculate a mean titre (never include [blank_start]rough[blank_end] values).
    1. Aglass pipette
    2. Bindicator
    3. Cdistilled water
    4. Dconical flask
    5. Epermanent
    6. Ffunnel
    7. Gair bubbles
    8. Hconcordant
    9. Iburette
    10. Jwhite tile
    11. Krough
  5. 5Using distilled water to rinse the sides of the conical flask in an acid-base titration will negatively affect your results.
    1. AVerdadero
    2. BFalso
  6. 6Why do you remove the funnel from the burette during a titration?
    1. ASo that any remaining droplets of solution do not fall into the burette and so change the volume/titre value.
    2. BTo stop you knocking it out/it falling out when adjusting the clamp to allow you to read the meniscus.
    3. CSo that it can be used by another group.
  7. 7Which of the following is NOT a suitable indicator for use in ANY titration?
    1. APotassium permanganate solution
    2. BMethyl orange solution
    3. CUniversal indicator solution
  8. 8Experimentally finding the enthalpy change of combustion
    Stage 1: preparing the chemicals
    • Add the fuel to the [blank_start]spirit burner[blank_end] and record the initial mass.
    • Add a known quantity of water to the [blank_start]calorimeter[blank_end] and clamp in position above the spirit burner.
    • Use thermometer to measure the initial temperature of the [blank_start]water[blank_end].
    Stage 2: carrying out the experiment
    • Use the spirit burner to heat water in the calorimeter to roughly (40ᵒC) and record the [blank_start]temperature change[blank_end].
    • Reweigh the spirit burner and calculate the [blank_start]change in mass[blank_end] of the fuel.
    Stage 3: interpreting the results
    • Calculate the energy released ([blank_start]J[blank_end]) using the equation q = mcΔT where q = [blank_start]energy change[blank_end]; m = mass of water heated; c = [blank_start]specific heat capacity of water[blank_end] (4.18); ΔT = change in temperature.
    • Calculate the enthalpy change ([blank_start]Jmol⁻1[blank_end]) using the equation ΔH = q / (moles of fuel).
    • Convert into [blank_start]kJmol-1[blank_end] by dividing your answer by 1000.
    1. Aspirit burner
    2. Bcalorimeter
    3. Cwater
    4. Dtemperature change
    5. Echange in mass
    6. FJ
    7. GJmol⁻1
    8. HkJmol-1
    9. Ispecific heat capacity of water
    10. Jenergy change
  9. 9Why are data book values often higher than those calculated experimentally?
    (CHOOSE 4)
    1. AHeat is lost to the surroundings, meaning the temperature change is smaller than it should be and so the enthalpy change value is smaller.
    2. BPeople make mistakes when doing experiments - the data book values are the values we would get if we always added the correct amount of water etc.
    3. COften, experimental values are not calculated under standard conditions.
    4. DThe technique has changed leading to more accurate values, but the data books have not been updated yet.
    5. EThe fuel will sometimes undergo incomplete combustion, meaning that the full amount of energy is not released.
    6. FAlcohols are very volatile and so some will evaporate from the wick. The value calculated for the number of moles of fuel burnt will be higher than the true value, meaning the value for enthalpy change will be lower than the true value.
  10. 10It is important to use a very precise thermometer when calculating the enthalpy change of a reaction.
    1. AVerdadero
    2. BFalso

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Test sobre Required Practicals for AQA A Level Chemistry INCOMPLETE, creado por Leah Firmstone el 24/04/2017.
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