C5

Front 1

What happens to mass during a chemical reaction, what may change this?

Back 1

The mass is conserved, this will not change. However mass measure may be:

Greater if gas gained from air

Less if water vapour of gas has been allowed to escape.

Front 2

How is the gas made or lost calculated?

Back 2

Calcite mass change.

Front 3

How do you convert between cm3 and dm3?

Back 3

Cm- dm = /1000

Dm- cm = *1000

Front 4

How does a concentrated solution compare to a dilute one? How is concentration measured?

Back 4

Solute particles are more crowded together, g/dm3 or mol/dm3

Front 5

How is a concentrated solution made more dilute?

Back 5

Adding water.

Front 6

Why must some concentrated solutions be diluted?

Back 6

Orange cordial is too strong tasting if not

Must carefully follow dilution instructions on medicines- if too dilute doesn't work, if too strong makes you more ill

If baby milk is not properly diluted may harm baby

Front 7

What does the GDA do? Why may sodium to sodium salt conversions be inaccurate?

Back 7

Informs you how much of a nutrient a person needs for a healthy diet each day. Sodium ions come from a number of sources.

Front 8

Give the word equation for a neutralisation reaction.

Back 8

Acid + alkali = salt + water

Front 9

Give the word equation for a neutralisation reaction.

Back 9

Acid + alkali = salt + water

Front 10

What is titration used to find out?

Back 10

How much acid is needed to neutralise an alkali.

Front 11

Describe the 8 step process of titration.

Back 11

-Measure the alkali in a conical flask by using a pipette and filler (stops acid contacting skin)

-Add indicator to flask

-Fill Burette with acid

-Record start volume of acid

-Add acid slowly until indicator changes colour

-Record end volume of acid

-Work out the titre

-To improve accuracy repeat to find consistent results and find a mean

Front 12

What is a titre and what does it depend on?

Back 12

The volume of acid that was added to neutralise the alkali. Depends on the concentration of reactants.

Front 13

Why is using a single indicator often better than using a mixed indicator?

Give an example of each.

Back 13

Shows change very clearly as there are not a range of colours on a spectrum only two.

Litmus

UI

Front 14

List the three main indicators and their colours when in acid or alkali.

Back 14

Litmus Ac red Ak blue

Phenolphthalein Ac colourless Ak pink

UI Ac red Ak blue

Front 15

How can the position of equilibrium be altered?

Back 15

By changing:

Temperature

Pressure

The concentration of reactants and products

Front 16

What does it mean if the position of the equilibrium lies to the right of the reaction equation?

Back 16

The concentration of the products is greater than the concentration of the reactants.

Front 17

What does it mean if the position of the equilibrium lies to the left of the reaction equation?

Back 17

The concentration of products is less than the concentration of the reactants.

Front 18

How do pressure and temperature affect equilibrium?

Back 18

Pressure increases product

Very high temperature decreases product

Front 19

What is made during the contact process?

Back 19

Sulfur, air and water are made into sulfuric acid.

Front 20

Give the steps involved in the contact process.

Back 20

-sulfur is burned in a furnace to make sulfur dioxide

-sulfur combines with oxygen in the air in a reversible reaction to make sulfur trioxide (takes place using a vanadium oxide catalyst at 450C and atmospheric pressure)

-Sulfur dioxide is then dissolved in water in an absorber to make sulfuric acid

Front 21

Give the word and symbol equations involved in each step of the contact process.

Back 21

1) Sulfur + oxygen = Sulfur dioxide

S + O2 = SO2

2) Sulfur dioxide + oxygen -- Sulfur trioxide

2SO2 + O2 -- 2SO3

2) Sulfur trioxide + water = sulfuric acid

SO3 + H2O = H2SO4

Front 22

What are some uses of Sulfuric acid?

Back 22

The manufacturing of:

-paints and pigments

-soaps and detergents

-fibres

-plastics

-fertilisers

Front 23

What apparatus are needed to collect and measure the volume of a gas made in a reaction?

Back 23

Upturned measuring cylinder

Gas syringe

Upturned burette

Front 24

Give the method used to measure the volume of gas produced in a reaction.

Back 24

-measure out reactants

-add reactants together in a conical flask and start the stopwatch

-record the volume of gas produced at regular intervals until the volume stops increasing

Front 25

Why does a reaction stop? What about in a 1-1 reactant ratio?

Back 25

Because the limiting reactant (reactant there is less of) gets used up. It's still the limiting reactant but the LR is the reactant with the fewest moles.

Front 26

Use particle theory to explain why the more reactant used the more product produced.

Back 26

More reactant particles means a greater number of collisions increasing the number of products particles. The number of limiting reactant particles is directly proportional to the amount of gas product particles produced.

Front 27

Give the experiment used the calculate the mass of gas produced in a reaction.

Back 27

-Measure mass of empty conical flask

-measure out reactants

-record total mass of reactants and flask

-add reactants together in the flask and start the stopwatch

-record the mass of the flask and reactants at regular intervals until the mass stops changing

Front 28

Give the rules to remember when sketching a graph to show volume of gas made in a reaction.

Back 28

-curve should be steepest at the beginning where the reaction is fastest

-curve should get shallower as the reaction progresses

-curve should become horizontal to show end of the reaction (should be level with the final volume of gas produced)

Front 29

Give an important rule that can be used to calculate the calculate the volume or amount of a gas?

Back 29

One mile of any gas occupies a volume of 24dm3 at room temperature and pressure.

Front 30

Give an example of a reversible reaction.

Back 30

Nitrogen + hydrogen -- ammonia

N2 + 3H2 -- 2NH3

Front 31

What is equilibrium in a reversible reaction?

Back 31

It reaches a balance where the rate of the forward reaction is equal to the rate of the backwards reaction. At equilibrium the amount and concentration of reactants and products stay the same even though reactions are taking place.

Front 32

What condition must be met for a reversible reaction to reach equilibrium? What is this called?

Back 32

The conditions such as temperature and pressure cannot be change and no substance is added or removed. This is known as a closed system.

Front 33

What determines the concentration of an acid?

Back 33

How many moles of the acid are dissolved in 1dm3.

Front 34

What determines the strength on an acid?

Back 34

How much it ionises, a strong acid produces more H+ ions than a weak acid of the same concentration because the weak acid does not ionise completely.

Front 35

What is the relegation ship between number of H+ ions and pH.

Back 35

The more H+ ions the lower the pH.

Front 36

Summarise why hydrochloric acid reacts quicker than ethanoic acid? (This can be generally applied)

Back 36

-hydrochloric acid is stronger than ethanoic acid

-hydrochloric acid has a greater concentration of hydrogen ions than ethanoic acid

-the greater concentration of hydrogen ions leads to a higher frequency of collisions between the hydrogen ions and the reactants.

Front 37

What is the relationship between acid strength and conductivity?

Back 37

A stronger acid has a greater concentration of hydrogen ions to carry electric charge so is a better conductor.

Front 38

What happens during the electrolysis of hydrochloric or ethanoic acid?

Back 38

Hydrogen gas is made at the negative electrode. This is because when electricity is passed through the acid, the hydrogen ions are attracted to the negative electrode where they become hydrogen molecules.

Front 39

When does a precipitation reaction occur?

Back 39

When a precipitate is made by mixing two ionic solutions together. The precipitate is made when ions from one solution collide with ions from another to make an insoluble compound,

Front 40

Give the method for making an insoluble compound.

Back 40

1) Mix the reactant solutions

2) Filter off precipitate

3) Wash the residue in the filter funnel with distilled water

4) Dry the residue in an oven at 50C

Front 41

What are halides?

Back 41

The ions made by the halogens.

Front 42

What substance can be used to detect halide ions and what precipitates are formed?

Back 42

Lead (II) nitrate.

Chlorides (Cl-) form a white precipitate

Bromides (Br-) form a cream precipitate

Iodides (I-) form a yellow precipitate

Front 43

What happens during an equilibrium reaction?

Back 43

The forward reaction will slow down and the backwards reaction will speed up until both reactions are at the same rate.

Front 44

What substance can be used to detect sulfate ions and what precipitate is formed?

Give the word equation.

Back 44

Barium chloride

White precipitate

Sodium sulfate (aq) + barium chloride (aq) = barium sulfate (s) + sodium chloride (aq)

Front 45

Give a characteristic of precipitate reactions.

Back 45

Very fast- precipitate forms almost instantly.

Front 46

What is a spectator ion?

Back 46

An ion dissolved in water that doesn't do anything.

Front 47

How can the equilibrium be moved to the right of the reaction equation?

Back 47

Adding more reactant

OR

Removing product as it is made

Front 48

How can the equilibrium be moved to the left of the reaction equation?

Back 48

Reducing the amount of reactant

OR

Increasing the amount of product

Front 49

What is the effect of an increase in pressure in a gas reaction?

Back 49

The increase pressure moves the equilibrium in the direction with the fewest moles of gas.

Front 50

Describe the compromised conditions used in the contact process.

Back 50

Vanadium catalyst used to speed up production of Sulfur trioxide but doesn't change position of equilibrium

Increasing temperature increases rate of reaction but reduces yield and pushes equilibrium position to the left (a compromised temp of 450C is used)

Increasing pressure increase yield and pushes the equilibrium to the right however is very expensive to maintain high pressure and not worth it for small increase so a medium high pressure is used

Front 51

What happens to acids and acids of differing strengths in water?

Back 51

Acids ionise in water to make hydrogen ions.

Strong acids ionise completely

Weak acids partially ionises, this is a reversible reaction so makes an equilibrium mixture

Front 52

What substances do ethanoic and hydrochloride acid react with and what is produced?

Back 52

Magnesium to produce hydrogen gas.

Calcium carbonate to produce carbon dioxide.

Front 53

Give a characteristic of precipitate reactions.

Back 53

Very fast- precipitate forms almost instantly. This is because there is a high chance of collisions.

Front 54

What is the volume of a gas made determined by? What affects the speed of the reactions?

Back 54

The amount of reactants used, not the acid's strength. The strength of the reactant i.e. the amount of hydrogen ions in a set concentration. For example there are fewer hydrogen ions in ethanoic than in the same concentration of hydrochloric so it reacts slower as there are fewer collisions.