chemistry paper 1

Question 1

Reactivity down group

Answer 1

New shell added so outer electrons further from nucleus
More shielding
So first ionisation energy decrease and reactivity increases

Question 2

Colour of iodine

Answer 2

Solid-grey/black
Gas-purple

Question 3

why shape

Answer 3

no of bond
no of lone
move to minimise replulstion
bond lone > bond bond

Question 4

polar based on polarity of bond

Answer 4

if no of bonds is even not polar
if odd polar as reinforce dipole

Question 5

how to write isotopes formulas

Answer 5

postive charge
may be multiple for each number
e.g
34 17+17 or 16+18

Question 6

decomposition temp

Answer 6

polarising power
larger radius polarises the bond less
so the bond of ion in common is stronger e.g nitrate
so more energy required to overcome bond

Question 7

how to draw ligands

Answer 7

from lone pairs to middle

Question 8

feasability in correlation to entrophy

Answer 8

more moles on the right of the equation
so entropy is positive

Question 9

gibbs equation

Answer 9

Question 10

conjugate base/acid

Answer 10

base
-proton acceptor - gains H+
-becomes more positive
acid
-proton donor - looses H+
-becomes more negative

Question 11

salt bridge chemical

Answer 11

KNO3
KCl

Question 12

how is max temp rise measured

Answer 12

extrapolation to orgional temp to line of best fit vertically up

Question 13

how is rate of decompositon of metal carbonates measured

Answer 13

bubble through lime water and measure time to go cloudy

Question 14

when conc of H+ = OH- what is the solution ph

Answer 14

neutral

Question 15

high or low Ka

Answer 15

Strong acids have high Ka values. The higher the Ka, the more the acid dissociates

Question 16

how to use curve to find Ka

Answer 16

half the eqivolence
10^-ph/10^-pka

Question 17

metalic bonding

Answer 17

strong electrostatic forces of attraction between a lattice of positively charged cations and a sea of delocalised electrons

Question 18

1s ionisation energy

Answer 18

energy required to overcome the bonds when one mole of gaseous atoms loses one mole of electrons to form one mole of gaseous 1+ ions

Question 19

assumtion for Ka

Answer 19

H+ = OH-
dissasociation is neglible

Question 20

why are theroeticla and experimental lattice values similar and not

Answer 20

similar -nearly 100% ionic
not similar- covalent character so polarises the bond

Question 21

what is enthlapy change

Answer 21

heat change at a constant pressure

Question 22

mass of the particles

Answer 22

proton + neutron - 1
electron - 1/1840

Question 23

why would something decompose even if not feasable

Answer 23

not standard conditions
not 1 moldm-3c
not 298 k
100 kpa

Question 24

how do sol act as buffers

Answer 24

contain a large amount of carbonate
ions and hydrogencarbonate ions
carbonate ions react with added hydrogen ions
hydrogencarbonate ions react with added hydroxide ions

Question 25

high kp

Answer 25

equilivrium lies to the right

Question 26

bonds in
O2
CO2

Answer 26

O=O
C=O

Question 27

what affects Kp

Answer 27

temperature

Question 28

Kp

Answer 28

equilibrium constant using partial pressures

Question 29

calculating partial pressure

Answer 29

Question 30

gibbs free energy

Answer 30

calculate wether a reaction is feasable (spontaneous)
if feasible gibbs is -
if not feasible its +
if equilibrium its 0

enthlapy change - temp(entropy change)

Question 31

equation of equilib constant and gibbs

Answer 31

ΔG = -RTlnK

Question 32

do orders in 17