Acids, Alkalis, Titrations, And Making Salts Flashcards
What colour does litmus paper go in acidic conditions
Red ( goes blue in alkaline conditions)
What colour will phenolphthalein go when a solution goes from acidic conditions to alkaline conditions
Colourless to bright pink
What colour does methyl orange go between a substance in acidic conditions to a substance in alkaline conditions
Red to yellow
What is an acid
A proton donor with a pH of less than 7 and is a source of H+ ions
What is a base
A substance that is a proton acceptor, has a pH of over 7, neutralises acids, and is a source of OH- ions
Show the ion representation of a neutralisation reaction
H+ + OH- = H20
What is produces when an acid and a metal oxide react
Salt + water
What is produced when an acid reacts with a metal hydroxide
Salt + water
What is produced when an acid and ammonia react
Ammonium salt
What happens when an acid and a metal carbonate react
Salt + water + carbon dioxide
Outline the process of carrying out a titration reaction
Use a pipette to add about 25cm^3 of alkali to a conical flask, and add a few drops of indicator as well
Fill a burette with the acid
Using the burette, gradually add the acid to the alkali and stir the mixture in the conical flask
When the indicator (phenolphthalein turns pink in alkalis but colourless in acids) changes colour, neutralisation has occurred
Record the volume of acid required to neutralise the alkali
Repeat this process 5 times and calculate a mean average to increase reliability
Read the results at the meniscus
What is the formula for titration calculations
Using moles, concentration, and volume
Moles = concentration x volume
How do you convert dm^3 into cm^3
Divide by 1000
Explain how you can use magnesium sulphate and lead nitrate to make an insoluble sample of lead sulphate
Add lead nitrate to a test tube and add water to dissolve it
Shake the test tube thoroughly to ensure all of the lead nitrate has dissolved
Do the same with magnesium sulphate
Add the two solutions into a beaker, the lead sulphate should precipitate out
Filter the contents of the beaker
Use distilled water to remove contamination/ensure sample is clean
Wash the soluble magnesium nitrate away and leave the lead sulphate to dry in an oven
Explain how you can use and acid and an insoluble base to make a soluble salt
Heat the acid in a water bath to speed up the reaction
Add the base to the acid, the excess base will solid will sink to the bottom of the flask following neutralisation
Filter any excess solid
Heat the solution using a Bunsen burner to allow water to evaporate
Leave the solution to cool and crystallise
Filter off the solid and leave it to dry
Why should you complete a reaction between an acid and an insoluble base in a fume cupboard
To avoid the release of acid fumes into the room
Explain how you can react an acid and an alkali together to make a soluble salt
Use a pipette to measure a set amount of acid
Add a few drops of an indicator e.g. phenolphthalein, don’t use universal indicator as the colour change is too gradual
Use a burette to slowly add alkali to the acid until neutralisation has occurred, shown by a colour change of the indicator
Carry out the reaction using the same volumes of acid and alkali but with no indicator to ensure there is no contamination of the salt
The solution remaining contains only the salt and water
Evaporate some of the water and leave the solution to crystallise
