DF

Question 1

molar gas equation

Answer 1

volume / molar gas volume

Question 2

at standard room temp and pressure 1 mole of any gas occupies…

Answer 2

24moldm^-3

Question 3

ideal gas equation

Answer 3

pV = nRT
p = pressure in pascals
v = volume in m^-3
n = moles
R = gas constant
t = temp in kelvin

Question 4

how do you measure the volume of a gas experimentally

Answer 4

measure amount of gas using a gas syringe, can’t be used if more than one type of gas is present. when the plunger doesn’t move any further the reaction has stopped and volume can be measured, be careful though as plunger may stop very quickly.

Question 5

what is enthalpy change of a reaction and what units is it measured in?

Answer 5

heat change in a reaction at constant pressure, measured in kjmol^-1

Question 6

what are standard conditions

Answer 6

temperature of 298k and 100kpa pressure and 1moldm^-3 concentration

Question 7

endothermic vs exothermic reactions

Answer 7

endothermic = absorbs energy from surroundings.
exothermic = release energy to surroundings

Question 8

what type of process is bond making?

Answer 8

exothermic as it releases energy

Question 9

what type of process is bond breaking?

Answer 9

endothermic as it requires energy

Question 10

standard enthalpy change of neutralisation

Answer 10

enthalpy change when when an acid and alkali react to form one mole of water under standard conditions

Question 11

standard enthalpy change of combustion

Answer 11

enthalpy change when one mole of a substance is completely burned in oxygen to make CO2 and H20 under standard conditions

Question 12

standard enthalpy change of formation

Answer 12

enthalpy change when one mole of a compound is formed from its elements in their standard states, under standard conditions

Question 13

calorimetry practical

Answer 13

.a fuel is lit up and burned underneath a beaker of water - the fuel raises the temperature of water by a specific amount.
. the energy is transferred from the fuel to the water however some is lost to surroundings
. to prevent energy loss we can use a lid on the beaker.
. weigh the fuel before and after we burn it.

Question 14

how do you calculate energy loss or gained

Answer 14

q = mc delta t

m= mass of water in g
c = specific heat capacity g^-1k^-1
t = temp in kelvin

Question 15

define a catalyst

Answer 15

a substance that increases the rate of a reaction by providing an alternative pathway that has a lower activation energy. the catalyst is chemically unchanged at the end of a reaction

Question 16

what is cracking

Answer 16

the process of breaking a longer chained hydrocarbon to shorter hydrocarbons

Question 17

heterogenous catalyst

Answer 17

catalyst that is in a different state to the reactants

Question 18

how can you increase rate of reaction using a heterogenous catalyst

Answer 18

increasing the surface area as more particles can react with the catalyst at the same time

Question 19

describe reactions that could occur on a heterogenous catalyst

Answer 19

.substances adsorb onto surface of catalysts
. the bonds in the reactants weaken and form radicals
. these radicals react to form new substances
. these substances desorb from the surface.

Question 20

define saturated

Answer 20

each carbon is bonded 4 times, eg in an alkane

Question 21

give an example of unsaturated

Answer 21

alkene

Question 22

what type of reaction can alkenes undergo

Answer 22

addition

Question 23

arenes/ aromatic compounds

Answer 23

organic molecules that contain a benzene ring

Question 24

aliphatic

Answer 24

non aromatic compounds (eg alkanes and alkenes)

Question 25

angle around each bond in an alkane

Answer 25

109.5 degrees

Question 26

homologous series

Answer 26

group of compounds that have the same functional group + general formula

Question 27

structural isomer

Answer 27

same molecular formula different structural formula

Question 28

E/Z and cis and trans?

Answer 28

E = opposite side | Z = same side
trans = opposite side when there’s no hydrogens | cis = same side when theres no hydrogens

Question 29

test for alkenes

Answer 29

adding bromine water to an alkene causes a colour change from brown-orange to colourless

Question 30

what are polymers made from

Answer 30

monomer units

Question 31

describe what happens when em radiation from the sun is absorbed by the earth

Answer 31

some of the radiation is re-emitted as infrared. some of the greenhouse gases absorb this infrared and re-emit them back to the earth - this is known as the greenhouse effect.

Question 32

problems of incomplete combustion

Answer 32

.carbon monoxide is poisonous but can be removed using a catalytic converter
.soot can cause breathing issues

Question 33

what is photochemical smog

Answer 33

it is formed when there is a mix of carbon particulates and ozone

Question 34

catalytic converters

Answer 34

mainly found in cars, they reduce the level of harmful pollutants by converting them into less harmful gases.