Unit 6 Flashcards
method for the measurement of the molar volume of a gas
- Set up the apparatus to capture and measure gas evolved from a reaction in the boiling tube
- Place 30cm3 of 1 moldm-3 ethanoic acid in the boiling tube
- Place approximately 0.05g of calcium carbonate in a test tube. Weigh the test tube and its contents accurately
- Remove the bung from the boiling tube and tip the calcium carbonate into the boiling tube. Quickly place bung in the boiling tube
- Once the reaction is over, measure the volume of gas produced
- Reweigh the test tube that contained calcium carbonate.
7.Repeat 6 more times, increasing the mass of calcium carbonate by about 0.05g each time. Do not exceed 0.40g of calcium carbonate
Equipment for the measurement of the molar volume of a gas
-boiling tube
-stand and clamp
-bung fitted with delivery tube to fit boiling tube
-water bath for gas collection
-100 cm3 measuring cylinder
- 50 cm3 measuring cylinder
-test tube
-mass balance
-1 moldm-3 ethanoic acid
-powdered calcium carbonate
safety procedures for the measurement of the molar volume of a gas
-wear eye protection
-remove the bung if the delivery tube gets blocked, clear the blockage and repeat the procedure from the start
- avoid skin contact with the ethanoic acid, especially if the skin is broken or sensitive
method for determination of the enthalpy change of a reaction using Hess’s Law
- Place an approximately 3g of solid potassium carbonate in a test tube. Accurately weigh the test tube and its contents
- Use a burette to dispense 30cm3 of 2 moldm-3 hydrochloric acid into a polysterene cup, which is supported in a beaker
- Measure the temperature of the acid
- Gradually add potasium carbonate to the acid, stirring all the time and monitoring the temperature of the acid
- Reweigh the empty test tube
6.Repeat 1-5 using 3.5g of potassium hydrogencarbonate instead. Record the lowest temperature reached.
equipment for determination of the enthalpy change of a reaction using Hess’s Law
-two test tubes
-2 moldm-3 dilute hydrochloric acid
-solid potassium carbonate
-solid potassium hydrogen carbonate
-thermometer able to read up to 50ºC
-polysterene cup
-250cm3 or 400cm3 beaker
-burette, clamp, stand
-stirring rod
-mass balance
-spatula
safety procedures for determination of the enthalpy change of a reaction using Hess’s Law
-wear eye protection
-avoid skin contact with the reactants and products
method for finding the concentration of a solution of hydrochloric acid
1.Wash out the 250cm3 volumetric flask with distilled water
2.Use the pipette to tranfer 25cm3 of the hydrochloric acid solution into the volumetric flask. Use distilled water to make the solution up to the mark.
3. Prepare your apparatus for the titration. The burette should contain the sodium hydroxide solution and the conical flask should contain the dilute hydrochloric acid solution.
4. Pour a 25cm3 aliquot of the diluted hydrochloric acid into the conical flask. Use phenolphthalein as the indicator.
5. Titrate the contents of the flask against the sodium hydroxide solution. Record all burette readings to the nearest 0.05cm3
6. The end point is indicated by the contents becoming pale pink and insisting 5 seconds while swirling.
7. Conduct further titrations unitl you have two concordant titres
8. record results in a table
equipment for finding the concentration of a solution of hydrochloric acid
-burette, clamp and stand
-sodium hydroxide solution (0.08dm3 previously standardised)
-bench hydrochloric acid ( 1mol dm-3)
-phenolphthalein
-250cm3 conical flask
-25cm3 volumetric pipette plus safety filler
-100cm3 beakers for transfer of solutions
-funnel for filling burette
-250cm3 beaker
-250cm3 volumetric flask
safety procedures for finding the concentration of a solution of hydrochloric acid
-wear eye protection
-avoid skin contact with acid, alkali or indicator
-always use a pipette filler
-take care when clamping and filling the burette that it does not crack or topple over
calculation for number of moles in full volume using an aliquot volume
(full volume)(no. of moles in aliquot volume) / aliquot volume in which you know moles = no. of moles in full volume
method for preparation of a standard solution from a solid acid and its use to find the concentration of a solution of sodium hydroxide
1.Weigh an empty test tube. Scoop approximately 2.5g of sulfamic acid into the test tube.
2.Accurately reweigh the test tube and its contents
3. Dissolve the sulfamic acid in approximately 100cm3 of water in a beaker
4. Transfer the solution, including the washings, to a 250cm3 volumetric flask and use distilled water to make up the solution to the mark.
5. Prepare your apparatus for the titration. The burette will contain the acid and the conical flask will contain the sodium hydroxide solution
6.Pour a 25cm3 aliquot of sodium hydroxide solution of unknown concentration into the 250cm3 conical flask
7. Use of methyl orange as the indicator
8.Titrate the contents of the flask against sulfamic acid solution prepared. Conduct further titrations until you have two concordant titres
equipment for preparation of a standard solution from a solid acid and its use to find the concentration of a solution of sodium hydroxide
-burette, clamp and stand
-solid sulfamic acid
-sodium hydroxide solution of unknown concentration
-methyl orange indicator
-250cm3 conical flask
-25cm3 volumetric pipette plus safety filler
-100cm3 beaker for transfer of solutions
-funnel for filling burette
-250cm3 beaker
-250cm3 volumetric flask
-mass balance
safety procedures for preparation of a standard solution from a solid acid and its use to find the concentration of a solution of sodium hydroxide
-wear eye protection.
-avoid skin contact with acid or alkali
-take care when clamping and filling the burette that it does not crack or topple over
method for the investigation of the rates of hydrolysis of some halogenoalkanes
1.Set up a water bath by filling the 250cm3 beaker up to the three-quarters mark with water at around 50ºC
2. Take three test tubes and add 5 cm3 of ethanol to each one
3. Add four drops of 1-iodobutane to the first tube, four drops of 1-bromobutane to the second tube and four drops of 1-chlorobutane to third tube. Label the tubes.
4. Loosely place a bung in each test tube and place the test tubes in the water bath
5. Take three clean test tubes and pour 5cm3 of silver nitrate solution into each one. Then place the test tubes in the water bath.
6. When the halogenoalkane-ethanol solutions have reached the temperature of the water bath, add one test tube of silver nitrate solution to one of the halogenoalkane-ethanol solutions and replace the bungs. At the same time, start the stop clock.
7. Measure the time taken for a precipitate to appear. As soon as the solution becomes cloudy, stop the clock.
8. Repeat steps 6 and 7 for each halogenoalkane, repeat 1-7 again for 1-bromobutane, 2-bromobutane and 2-bromo-2-methylpropane instead of halogenoalkanes.
equipment for the investigation of the rates of hydrolysis of some halogenoalkanes
-250cm3 beaker
-12 test tubes with bungs
-1-chlorobutane
-1-bromobutane
-1-iodobutane
-2-bromobutane
-2-bromo-2-methylpropane
-0.05moldm-3 silver nitrate solution
-15cm3 of ethanol
-dropping pipettes
-two 10 cm3 measuring cylinders
-stop clock
-labels for test tubes
-kettle
safety procedures for the investigation of the rates of hydrolysis of some halogenoalkanes
-wear eye protection
-avoid skin contact with the reactants
-no naked flames as ethanol and halogenoalkanes are highly flammable
-well ventilated laboratory to prevent inhalation of fumes
method for making propanal (7a)
- Wear protective gloves when handling acidified potassium dichromate solution. Carefully add 20cm3 of acidified potassium dichromate solution to a 50cm3 pear-shaped flask. Cool the flask in ice-water bath.
- Set the flask up for distillation, keeping it in the ice-water
3.Place a few bumping granules into the pear-shaped flask - Measure 1.5cm3 of propan-1-ol into a measuring cylinder and add 5cm3 of distilled water to this
- Using a pipette, add the propan-1-ol solution, a few drops at a time, into the pear-shaped flask
- When all propan-1-ol has been added, remove ice-water bath and allow the flask to warm to room temp.
- Light a bunsen burner under the flask and heat very gently with a small flame
- Collect 3-4 cm3 of clear, colourless liquid in a test tube which is immersed in cold water in a beaker.
method for testing for propanal (7b), silver mirror test
- Prepare a sample of Tollen’s reagent by adding 5 drops of sodium hydroxide solution to 2 cm3 of silver nitrate solution in a test tube
2.Add just enough ammonia solution to this test tube so that the brown ppt dissolves completely. Using water bath, gently warm this test tube - Add 10 drops of the distillate (created after making propanal). If propanal has been produced, a silver mirror will appear
method for testing for propanal (7b), magnesium ribbon
- Add a small piece (1cm) of magnesium ribbon to the distillate .
- Observe if a reaction happens, Propanal should not react with magnesium
method for testing for propanal (7b), sodium hydrogencarbonate
- Add spatula of sodium hydrogencarbonate to the distillate in a test tube
- Propanal should not produce any effervescence
method for testing for propanal (7b), Fehling’s solution
- Add 1cm3 Fehling’s solution to 1cm3 of the distillate in a test tube
- Place test tube into a beaker of hot water. A colour change to reddish brown indicates propanal is present
equipment for making and testing for propanal. making andtesting for propanoic acid
-simple distillation apparatus
-acidified potassium dichromate (VI)
-propan-1-ol
-distilled water
-teat pipette
-Bunsen burner
-stand and clamp
-measuring cylinders
-anti-bumping granules
-test tubes
-spatula
-thermometer
-10cm3 beakers
-0.05 moldm-3 silver nitrate solution
-2 moldm-3 dilute ammonia solution
-2 moldm-3 sodium hydroxide solution
-small pieces of magnesium ribbon
-sodium hydrogencarbonate
-Fehling’s solution