separate chemistry

Question 1

what are the typical properties of transition metals

Answer 1

-hard
-strong
-shiny
-conduct heat and electricity

Question 2

what are alloys

Answer 2

they are made by adding another element to a metal. this can be a metal or a non metal

Question 3

why are alloys stronger than pure metals

Answer 3

as the other element will stop the layers of the metal from sliding over each other. this means that the alloy is less malleable

Question 4

how is the alloy steel made

Answer 4

by adding small amounts of carbon to the pure iron

Question 5

how is the alloy bronze made

Answer 5

copper + tin

Question 6

what is bronze used for

Answer 6

medals, statues and decorations

Question 7

how is the alloy brass made

Answer 7

copper+zinc

Question 8

what is brass used for

Answer 8

water taps and door fittings

Question 9

how pure is 24 carat gold

Answer 9

100%

Question 10

how pure is 18 carat gold

Answer 10

75%

Question 11

what is aluminium alloys used for

Answer 11

to make aircrafts

Question 12

how is the alloy magnalium made

Answer 12

aluminium+magnesium

Question 13

what is magnalium used for

Answer 13

make parts for cars and aeroplanes

Question 14

why do metals corrode

Answer 14

due to the presence of oxygen which causes oxidation

Question 15

what is rusting

Answer 15

this is the corrosion of iron

Question 16

what are the 3 ways to prevent rusting

Answer 16

painting
-electroplating
-sacrificial protection

Question 17

how does painting prevent rusting

Answer 17

it creates a physical barrier between the metal and the air

Question 18

how does sacrificial protection prevent rusting

Answer 18

this involves placing a more reactive metal with the metal you want to protect. the oxygen will then react with the more reactive metal. however, the more reactive metal will need to be constantly replaced

Question 19

what is electroplating

Answer 19

coating the surface of a metal with another metal using electrolysis

Question 20

how do you do electroplating

Answer 20

-your cathode is the object your going to electroplate
-your anode is the bar of metal your using for the plating
-your electrolyte is the solution containing the metal ion of the metal your using for the plating

Question 21

why are titration experiments used

Answer 21

to find out concentrations of a liquid

Question 22

what is the formula for concentration

Answer 22

moles/volume

Question 23

how do you do titration calculations

Answer 23

-find out the moles of the known
-use equation to do mole ratio to find out moles of unknown
then work out the concentration

Question 24

what is the formula for percentage yeild

Answer 24

actual yeild/ theoretical yield *100

Question 25

how to do percentage yield calculations

Answer 25

work out no. moles of reactant -use balance equation to do mole ratio -work out mass of this using moles -then find percentage yield

Question 26

what is atom economy

Answer 26

the percentage of the reactants has been turned into the desired product

Question 27

what is the formula for atom economy

Answer 27

total mr of desired products/ total mr of all the products *100

Question 28

what is the chemical equation of the haber process

Answer 28

N2+H2=NH3

Question 29

what does the haber process produce

Answer 29

ammonia

Question 30

what are the three main elements in fertilisers that plants need

Answer 30

nitrogen phosphorus and potassium

Question 31

what is the molar volume

Answer 31

this is the volume occupied by one mole of a gas

Question 32

what is the formula for molar volume

Answer 32

volume/number of moles

Question 33

what is avogadros law

Answer 33

one mole of any gas occupies 24dm3 or 24000cm3 at room temperature and pressure

Question 34

what is a fuel cell

Answer 34

this is a type of chemical cell thats supplied with fuel and oxygen to produce electrical energy

Question 35

what fuel do hydrogen-oxygen fuel cell use

Answer 35

hydrogen

Question 36

what is the equation for the hydrogen-oxygen fuel cells

Answer 36

hydrogen+oxygen= water

Question 37

what are the advantages of hydrogen-oxygen fuel cells

Answer 37

no pollutants produced

Question 38

what are the disadvantages of hydrogen-oxygen fuel cells

Answer 38

-needs lots of space to store -it is explosive so it is also difficult to store