Acids,10

Question 1

Acid / Alkali

Answer 1

Hydrochloric ACID = acid, HCl
Sodium HydrOXIDE = alkali, NaOH

Question 2

What contains acid?

Answer 2

Acid contains hydrogen ions (H^+). These cause a solution to be acidic.

Question 3

We can find the pH of a solution by….

Answer 3

1. Adding universal indicator to the solution and comparing colour to pH chart.
2. Using a pH probe.

Question 4

Indicator, colour in acid, colour in neutral, colour in alkali, universal acid

Answer 4

Colour in acid: Red

Colour in neutral: yellow or green

Colour in alkali: blue or purple

Question 5

Indicator, colour in acid, colour in neutral, colour in alkali, Litmus

Answer 5

Colour in acid: Red

Colour in neutral: Blue/ Violet

Colour in alkali: Blue

Question 6

Indicator, colour in acid, colour in neutral, colour in alkali, methyl orange

Answer 6

Colour in acid: Red

Colour in neutral: Orange

Colour in alkali: Yellow

Question 7

Indicator, colour in acid, colour in neutral, colour in alkali, Phenolphthalein

Answer 7

Colour in acid: colourless

Colour in neutral: colourless

Colour in alkali: pink

Question 8

Concentration

Answer 8

1. Concentration = is to do with the number of particles dissolved in a volume of water.
   - Lots of particles in a volume of liquid.
2. Dilute = not many particles in the same volume of liquid.

Question 9

pH & concentration

Answer 9

• the concentration of hydrogen ions is linked to pH.
• the more hydrogen ions the lower the pH.
• if the concentration is increased by a factor of 10 the pH decreases by 1.

Question 10

Neutralisation

Answer 10

• a chemical reaction where an acid and a base cancel each other out to produce a solution of pH7.
• a salt and water is formed,
  acid+base => salt+water
• acid = 0=>7 ;alkali = 7=> 14; neutral = 7
• bases neutralise acids.
• alkali are soluble bases.

Question 11

Preparing a soluble salt

Answer 11

1. Measure out sulphuric acid with measuring calendar.
2. Careful heat the acid.
3. Use an espactula add copper acide to the acid.
4. Stir the solution with a glass rod.
5. Continue adding copper oxide until some is left in the bottom.
6. Filter the mixture to remove and react copper oxide.
7. Heat the solution in evaporated basin until half is left.
8. Leave evaporated base in evaporated a warm place.
9. Dry crystals between filter paper.

Question 12

Bases and Alkali

Answer 12

Acid + Base => Salt + Water

Acid + Alkali => Salt + Water

Question 13

First Method of producing soluble salt.
Acid and bases.

Answer 13

Stage 1:
Warmed mixture of excess base and acid.

Stage 2:
- mixture of excess base and salt solution.
- filter paper to remove excess insoluble base.
- filter funnel.
- aqueous salt solution ready for evaporation.

( heat. Remove half of solution. Leave in warm place. Dry crystals.)

Question 14

Second method of producing soluble salt

Answer 14

Acids and alkalis.
- slowly add acid to alkali until indicator changes colour.
- record volume of alkali used.
- repeat using SAME volumes of acid and alkali BUT without indicater.
- put in evaporate base and crystallise.
( heat. Remove half of solution. Leave in warm place. Dry crystals.)

Question 15

Acid + Metal

Answer 15

Acid + Metal => Salt + Hydrogen

Question 16

Acid + Metal Carbonate

Answer 16

Acid + Metal Carbonate => Slat + Water + Carbon dioxide

Question 17

Precipitates

Answer 17

Precipitates solid suspended in solution ( cloud filter mixture to give solid only, then dry with filter paper).

Question 18

Soluble in water:

Answer 18

1. All common sodium, potassium and ammonium salts.
2. All nitrates.
3. Most chlorides.
4. Most surfaces.
5. Sodium, potassium and ammonium carbonates / hydroxides.

Question 18

Insoluble in water:

Answer 18

1. Silver, lead chlorides.
2. Lead barium, calcium sulfates.
3. Most carbonates and hydroxides.

Question 19

Sodium carbonate + copper chloride

Answer 19

Sodium carbonate + copper chloride
=
Sodium chloride + copper carbonate