Physical Chemistry

Question 1

Colour of Phenolphthalein in acid and alkaline

Answer 1

Colourless in acidic solutions

Bright pink in alkaline solution

Question 2

Colour of Methyl orange in acids and alkaline solution

Answer 2

Red in acidic

Yellow alkaline

Question 3

Colour of Litmus paper in acid and and alkaline and neutral

Answer 3

Red in acid
Blue in alkaline
Purple in neutral

Question 4

Acid + Metal Oxide —>

Answer 4

Salt + Water

Question 5

Hydrochloric acid + Copper oxide —>

Answer 5

Copper Chloride + Water

Question 6

Acid + metal carbonates —>

Answer 6

Salt + Water + Carbon Dioxide

Question 7

Sulfur is acid + Calcium Carbonate —>

Answer 7

Calcium Sulfate + water + Carbon Dioxide

Question 8

An acid is a source of….

Answer 8

Hydrogen ions (H+)

Question 9

An alkali is a source of…

Answer 9

Hydroxide ions (OH-) ions

Question 10

The reaction between an acid and an alkali is called what?

Answer 10

Neutralisation

Question 11

Name 6 salts that are soluble

Answer 11

Sodium
Potassium 
Ammonium 
Nitrates 
Chlorides 
Sulfate

Question 12

Name a salt that’s insoluble

Answer 12

Most Carbonates

Except sodium, potassium and ammonium carbonates

Question 13

What reaction do you use to make Insoluble salts?

Answer 13

Precipitation - Must mix two solutions containing the ions you need

Question 14

Barium Chloride + Sulfuric Acid —>

Answer 14

Barium Sulfate + Hydrochloric acid

Question 15

Name the Chloride that’s insoluble q

Answer 15

Silver Chloride

Question 16

Name the 2 sulfates that are insoluble

Answer 16

Barium Sulfate and Calcium Sulfate

Question 17

4 things that affect the rate of reaction

Answer 17

Concentration
Catalyst
Temperature
Size of Particles

Question 18

Equation for rate of Reaction

Answer 18

Amount of reactant used or product formed/ Time

Question 19

What causes faster collisions?

Answer 19

Increase in temperature
At higher temp there will be more particles colliding with enough energy to make the reaction happen ( more successful collisions)

Question 20

Bond Breaking =

Answer 20

Endothermic

Question 21

Bond forming =

Answer 21

Exothermic

Question 22

What is the change in energy called

Answer 22

The Enthalpy change

Question 23

Name a reversible reaction

Answer 23

Thermal decomposition of ammonium chloride dehydration of Copper (||) Sulfate

Question 24

Closed system =

Answer 24

No reactants or products escape

Question 25

What is Dynamic Equilibrium

Answer 25

Reactions are taking place in both directions forward and backwards and the rate of reaction is the same in both directions

Question 26

Describe how temperature and gas can get you more product.

Answer 26

Raise temp means endothermic reaction will increase to use up the extra heat Raised pressure encourages the reaction which produces fewer molecules of gas

Question 27

When making soluble salts using acids and insoluble bases, when will you know the acid has been neutralised?

Answer 27

Excess solid will sink to the bottom of the flask and remain there

Question 28

What are Titrations? How do you carry one out?

Answer 28

Used to find out concentrations; allow you to find oh exactly how much acid is needed to neutralise a quantity of alkali or vice versa 1Using a pipettes and pipettes filler add some alkali usually about 25 cm3 to a conical flask, along with 2 or 3 drops of indicator 2. Fill a beretta with the acid: do below eye level, don't want to be looking up if some acid spills over 3. Using the burrette - add the acid to the alkali a bit at a time giving the conical flask a regular swirl. Go especially slowly when you think the end-point (colour change) is about to be reached 4. Indicator changes colour; record the volume of acid used to neutralise alkali; repeat a few times to make sure you get the same answer making it more reliable

Question 29

How can you calculate the Enthalpy change?

Answer 29

Energy for bond breaking - Energy for making bonds

Question 30

What is Calorimetry?

Answer 30

Allows you to measure the amount of energy transferred in a chemical reaction With pretty simple set of equipment

Question 31

How can you measure the amount of energy transferred in dissolving, displacement and neutralisation reactions?

Answer 31

Take temperature of the reagents (making sure they're the same), mix them and measure the temperature of the solution at the end of the reaction Mix in a polystyrene cup

Question 32

One of the biggest problems with measuring the amount of energy transferred in dissolving, displacement and neutralisation reactions is the energy lost to its surroundings. How can you reduce this?

Answer 32

Putting the polystyrene cup into a beaker of cotton wool to give more insulation and putting a lid on the cup to reduce energy lost by evaporation

Question 33

Describe how you can measure the energy transferred in a neutralisation reaction

Answer 33

1. Place 25cm3 of dilute Hydrochloric acid in a polystyrene cup and record the temp of acid 2. Put 25cm3 of dilute sodium hydroxide in a measuring cylinder and record it's temp 3. Add alkali to acid and stir 4. Take the temperature of the mixture every 30 seconds and redid the highest temperature it reaches

Question 34

In the experiment to measure the amount of energy produced when a fuel is burnt, why is the metal container made of copper?

Answer 34

Copper conducts hear so well

Question 35

Describe how you can measure the amount of energy produced when a fuel is burnt?

Answer 35

1. Put 50g of water in the copper and record it's temperature 2. Weigh the spirit burner and lid 3. Put spirit burner underneath the can and light the wick 4. Heat the water, stirring constantly until the temperature reaches about 50 degrees; put out flame using the burner lid and measure final temp 5. Weigh the spirit burner and lid 6. Use the measurements to calculate Enthalpy change

Question 36

What important in the experiment to measure the amount of energy produced when a fuel is burnt?

Answer 36

Make as much heat as possible to into heating up the water | Reducing draughts is the key here- use a screen to act as a draught excluder ( don't do it next to the window?