Mass Calculations, Electrolyisis, Metals And Equilibria T5

Question 1

What happens to atoms during a chemical reaction?

Answer 1

No atoms are created and no atoms are destroyed, this means there are the same number and types of atoms on each side

Question 2

Why might the mass increase in a reaction?

Answer 2

If the mass increases, it’s probably because at least one of the reactants is a gas that is found in air. Before the reaction, gas is floating in the air and floats into the reaction vessel and

Question 3

Why might the mass decrease in the reaction?

Answer 3

If the mass decreases, it’s probably because some, or all, of the reactants are solids, liquids or aqueous and at least one of the products is a gas. Before the reaction, any solid, liquid or aqueous reactants are contained in the reaction vessel, if the vessel isn’t sealed, gas can escape when its formed

Question 4

What is a closed system reaction?

Answer 4

Where nothing can get in or out so the mass doesn’t change

Question 5

What is the relative formula mass?

Answer 5

The atomic masses of all of the atoms in it’s formula added toegther

Question 6

What is the empirical formula?

Answer 6

The empirical formula tells you the smallest whole number ratio of atoms in the compound

Question 7

What is the empirical formula of glucose?(C6H12C6)

Answer 7

CH2O

Question 8

What is “The mole”?

Answer 8

The mole is simply the name given to a certain number of particles

Question 9

What is Avogrado’s constant?

Answer 9

6.02 x 10^23

Question 10

How do you work out the number of moles?

Answer 10

Number of moles = mass in g / total relative mass

Question 11

How do you work out concentration

Answer 11

Concentration = mass of solute / volume of solution

Question 12

What are the typical properties of transition metals?

Answer 12

They’re relatively hard and strong,conduct heat and electricity, they have high melting and boiling points and have high densities

Question 13

What does a catalyst do?

Answer 13

A catalyst up the rate of reaction without being changed. Iron is used as a catalyst for making ammonia.

Question 14

Why are pure metals malleable?

Answer 14

Because they have a regular arrangement of identical atoms. The layers of ions can slide over each other.

Question 15

How are alloys made?

Answer 15

Alloys are made by adding an extra element to the metal to make it stronger, this makes the atom less regular and so they don’t easily slide over each other

Question 16

What happens when metals corrode in the presence of oxygen?

Answer 16

They form metal oxides

Question 17

Why is the corroding of metals a redox reaction?

Answer 17

Because the metal loses atoms , it’s oxidised while the oxygen gains them

Question 18

What is rusting?

Answer 18

Rusting is the name for corrosion of iron, rusting only happens when the iron is in contact with both oxygen and water

Question 19

What is sacrificial protection?

Answer 19

This involves placing a more reactive metal with iron. Water and oxygen react with this ‘sacrificial metal’ rather than the iron

Question 20

What is galvanising?

Answer 20

Galvanising is an example of sacrificial protection, where a coat of zinc is put over an iron object

Question 21

What is electroplating?

Answer 21

Electroplating is coating the surface of a material with another metal using electrolysis

Question 22

How do you electroplate?

Answer 22

The cathode is the object you’re going to electroplate, the anode is the bar of metal you’re using for the plating. Your electrolyte is a solution containing metal ions of the metal you are plating. The anode’s ions move over and deposit themselves onto the cathode

Question 23

What does oxidation mean?

Answer 23

The reaction with, or the addition of oxygen

Question 24

What is reduction?

Answer 24

The removal of oxygen

Question 25

What type of reaction is combustion?

Answer 25

Exothermic

Question 26

What is a reactivity series?

Answer 26

A reactivity series is a table that lists metals in order of their reactivity

Question 27

Why is carbon often included in a reactivity series?

Answer 27

A metal’s position in the reactivity series compared to carbon dictates how it’s extracted from its ore

Question 28

What metals are placed at the top of a reactivity series?

Answer 28

The most reactive ones, but the least resistant to oxidation

Question 29

How can you measure how reactive a metal is?

Answer 29

The more easily a metal atom loses its outer electrons and forms a positive ion

Question 30

What experiment can you do to test the reactivities of metals?

Answer 30

Place little pieces of various metals into dilute hydrochloric acid, put lit splint over it after a certain amount of time, the louder the bang, the more reactive the metal is. This is because metals have a reaction with the hydrochloric acid which produces hydrogen, hydrogen produces a big bang when a lit split comes in contact with it

Question 31

What is the formula for a reaction with a metal and water?

Answer 31

Metal + water = metal hydroxide + hydrogen

Question 32

What is the name for when reduction and oxidation happen simultaneously?

Answer 32

Redox reaction

Question 33

What is a displacement reaction?

Answer 33

A more reactive element reacts to take the place of a less reactive element in a compound. During a displacement reaction, the more reactive metal is oxidised and the less reactive metal is reduced

Question 34

What is a metal ore?

Answer 34

A metal ore is a rock which contains enough metal to make it economically worth while to extract the metal from it

Question 35

What metals need to be extracted using electrolysis?

Answer 35

Metals which are higher than carbon in the reactivity sereis

Question 36

What metals can be extracted using reduction with carbon?

Answer 36

Metals below carbon in the reactivity series

Question 37

Why is electrolysis more expensive than reduction with carbon

Answer 37

In order to electrolysis, you need large amounts of electricity, electricity is expensive

Question 38

How does bioleaching work?

Answer 38

This uses bacteria to separate metals from their ores. The bacteria get energy from the bonds between the atoms in the ore, separating out metal from the ore in the process

Question 39

How does phytoextraction work?

Answer 39

This involves growing plants in soil that contain metal compounds. The plants can’t use or get rid of the metals so they gradually build up in the leaves. The plant then can be harvested, dried and burned in a furnace. The ash contains metal compounds

Question 40

What is the life cycle assessment?

Answer 40

The LCA looks at each stage of the life of a product | Choice of material, manufacture, product use and disposal

Question 41

What are reversible reactions?

Answer 41

Reactions which go forwards and backwards

Question 42

What is equilibrium?

Answer 42

When the forward reaction happens at the same rate as the backwards reaction, this is equilibrium

Question 43

What is the Haber process?

Answer 43

During the Haber process, nitrogen and hydrogen form to create ammonia

Question 44

What is a closed system?

Answer 44

A closed system just means that none of the reactants or product can escape

Question 45

What 3 things change the position if equilibrium?

Answer 45

Temperature, pressure and concentration

Question 46

What is le chatelier’s principle?

Answer 46

The principle states that if there’s a change in concentration, pressure or temperature in a reversible reaction, the equilibrium position will move to help counteract the change