Inorganic memory module 3

Question 1

periodicity

Answer 1

The repeating trends in properties of the elements

Question 2

First ionisation energy

Answer 2

The energy requires to remove one electron from ach atom of gaseous atoms of an elements to form one mole of gaseous 1+ ions.

Question 3

What affects ionisation energy

Answer 3

• atomic radius
• electron sheildign
• nuclear charge

Question 4

metallic bonding

Answer 4

The strong electrostatic attraction between a metal cation and a sea of delocalised electrons

Question 5

disproportionation

Answer 5

a redox reaction in which the same element is both oxidised and reduced

e.g. Cl2(aq)+2NaOH(aq) –> NaClO(aq) + NaCl (aq) + H20(l)

Question 6

Test for carbonates

Answer 6

1. Add dilute nitric acid
2. bubbles of C02 will be produced
3. bubble through lime water to turn turn cloudy

CO3- + NO3- –> NO3- + C02 + H20

Question 7

Test for sulfate

Answer 7

• add aqueous barium ions
• formation of white precipitate of barium sulfate

Ba2+ + SO4^2- –> BaSO4 (s)

Question 8

Test for Halides

Answer 8

1. Add aqueous silver nitrate to aqueous solution of halides
2. form silver halide precipitations (white, cream and yellow)
3. Add aqueous ammonia to test solubility

Ag+ + X- –> AgX (s)

chlorine - white, soluble in dilute NH3
Bromide - cream, soluble in concentrated NH3
Iodide - yellow, insoluble in concentrated NH3

Question 9

Correct sequences of tests

Answer 9

1. carbonate (no possibility of incorrect conclusions)
2. sulfate (Carbonate with also produce what precipitate)
3. halide (from silver carbonate and silver sulfate will not form precipitates)

Question 10

Enthalpy

Answer 10

The measure of heat energy in a chemical system

Question 11

calculation for enthalpy change

Answer 11

^H = H (Products) - H(reactants)

Question 12

Standard cons

Answer 12

• 298 k
• 100 kPa
• 1.00 mol dm-3

Question 13

The standard enthalpy change of reaction

Answer 13

^rH > the enthalpy change that accompanies a reaction in the molar quantities shown in the chemical equation under standard conditions, with all reactant and products in their standard conditions

Question 14

The standard enthalpy change of formations

Answer 14

The enthalpy changes that takes place when one mole of a compound is formed from is constituent elements, under standard conditions, with all reactant and products in their standard conditions

Question 15

The standard enthalpy change of combustion

Answer 15

The enthalpy change that accompanies the change that takes place when 1 mole of substance reacts completely with oxygen. Under standard conditions, with all reactant and products in their standard conditions

Question 16

The standard enthalpy change of neutralisation

Answer 16

The enthalpy changes the accompanies the reaction of an acid by a abase to form one mole of H20 (l). Under standard conditions, with all reactant and products in their standard conditions

Question 17

Specific heat capacity

Answer 17

energy required to raise the temperature of 1g of a substance by 1K

Question 18

calculate energy changes

Answer 18

q (joules)= mc^T
m = mass
c = water density

Question 19

Why is experimental ^cH values inaccurate

Answer 19

• heat loss to the surroundings other then water
• incomplete combustion
• evaporation of alcohol from the wick
• non-standard conditions

Question 20

Average bond enthalpies

Answer 20

The energy required to break one mole of a specific type of bond in a gaseous molecule (always endothermic)

enthalpy changes (^rH) = total bond enthalpy of reactants - total bond enthalpy of products

Question 21

limitation to bond enthalpy

Answer 21

• only average used meaning the actual quantity would be variable
• all species need to be gaseous molecules (so not standard enthalpy change calculated)

Question 22

Hess’ law

Answer 22

If a reaction can take place by two routes, and the starting and finishing conditions are the same the total enthalpy change in the same for each route

Question 23

Rate od a chemical reaction

Answer 23

measures how fast a reactant is being used or how fast a product is being formed.

rate = change in conc/time

Question 24

catalyst

Answer 24

a substance the increases the rate of a chemical reaction by providing an alternative reaction route with a lower activation energy, without a permeant change to itself
- homogenous (forms an immediate)
- heterogenous (provides a surface on which the reaction can take place)

Question 25

dynamic equilibrium

Answer 25

• rate of froward and backward reaction equal
• concentration of reactants and products do not change

Question 26

le chapeliers principale

Answer 26

when as system in equilibrium is subjected to an external change the system readjusts itself to minimise the effects of that change