chemistry only paper 2

what is solubility

maximum mass of a substance which will dissolve in 100g of solvent at a particular temperature

what is the definition of metallic bonding

the electrostatic attraction between positive metal cations and delocalised electrons

What is malleability?

the ability of a solid to be hammered without shattering

why are metals malleable

Layers of atoms can slide over each other when force is applied

Why are metals good conductors?

they have delocalised electrons which are free to move - can carry heat across the structure

what is ductile

able to be drawn out into a thin wire

do covalent compounds conduct electricity

no - fixed ions that are not free to move

when do ionic compounds conduct electricity and why

when molten or aqueous - freely moving particles

what is an anion

A negatively charged ion

what is a cation

A positively charged ion

what are ionic compounds called

electrolytes

what is electrolysis

the formation of new substances when ionic compounds conduct electricity

what happens to molten substances at the negative electrode

reduction - the metal is produced

what happens to molten substances at the positive electrode

oxidation - alkali is produced

what happens to aqueous substances at the negative electrode

if the metal is more reactive than hydrogen then hydrogen is produced - 2H+ + 2e- --> H2

what happens at the positive electrode in aqueous solutions

if anion is NOT a halide then oxygen if produced: 2H2O --> 4e- + O2 + 4H+

explain the trend in reactivity in group one alkali metals

reactivity increases as you go down the group - the metals lose an electron - the further down the more electron shells therefore less attraction to the nucleus - less energy to remove electron so more reactive

what is the reactivity in group 7

increases as you go up the group - need to gain electrons - requires less energy to gain electron if there is greater attraction to the nucleus due to less electron shell.

where are reactive metals found

ores found on the earths crust

how are unreactive metals often found

uncombined elements

what is an ore

an ionic compound from which the metal is removed for profit

how are metals lower than carbon extracted

using carbon in a displacement reaction

how are metals extracted that are higher than carbon in reactivity series

extracted using electrolysis - expensive process that requires lots of electricity

what is aluminiums use

lightweight/low density - car bodies, planes, bike frames

resists corrosion - drinks cans

copper use

unreactive - coins

conductor of heat - wiring / pots and pans

iron use

- strong - gates and fences

use of steels - low carbon / high carbon and stainless steel

- less than 0.25% carbon - car bodies, nails

- high carbon steel - 0.25-2.25% - cutting tools/bridges

- stainless steel - chromium added- cutlery / kitchen sinks

what is an alloy

A mixture of a metal and one of more elements, usually other metals or carbon

are alloys harder than pure metals and why

yes - contain atoms of different sizes which distorts layers, its more difficult to slide over each other

describe an energy level diagram for an exothermic reaction

reactants have more energy than the products / products less energy than the reactants

bond breaking is

endothermic

bond making is

exothermic

what is the delata H on the graph

line down or up from reactants to products

what is activation energy on the graph

the difference between the reactants and the top of the curve

what is a reversible reaction

a reactoin where the products can react together to form the original reactants

What is equilibrium?

when reactions occur at exactly the same rate in both directions

what is dynamic equilibrium

forward and backward reactions are both happening at the same time and at the same rate - the concentrations of reactants and products remain constant

when can dynamic equilibrium be reached

in a closed system

what affect does the catayust have on equilibrium

increases rate of reaction but does not affect the position of equilibrium

what will happen if you decrease the temperature

the equilibrium will move in the exothermic direction to produce more heat.

what will happen if you increase the temperature

the equilibrium will move in the endothermic direction to absorb more heat.

pressure only effects equilibrium in what

gases

what happens if you increase the pressure

The equilibrium will move towards the side that has fewer moles of gas to reduce pressure

what happens if you decrease the pressure.

The equilibrium will move towards the side that has more moles of gas to increase pressure

what happens if you increase the concentration of the reactants

the equilibrium will move to the right to consume the excess reactants.

what will happen if you increase the concentration of the products.

the equilibrium will move to the left to convert excess products to reactants.

what happens if you decrease the concentration of the reactants

equilibrium will shift to the left to produce more reactant + replace what was lost.

what will happen if you decrease the concentration of the products

equilibrium will shift to the right to produce more products + replace what was lost

what is the functional group of alcohols

OH-

how can ethanol be oxidised

- burning in air or oxygen (complete combustion)

- reaction with oxygen in the air to form ethanoic acid (microbial oxidation)

- heating with potassium dichromate in dilute sulfuric acid to form ethanoic acid

how can ethanol be manufactured by

reacting with ethene with steam in the Prescence of a phosphoric acid catalyst at a temperature of 300 degrees and pressure of 60-70

fermentation of glucose - without air - temperature of 30 degrees and enzymes in the yeast

functional group of carboxylic acid

COOH

carboxylic acids react with metals to produce

salt + hydrogen

carboxylic acids react with metal carbonates to produce

salt, water and CO2

what is vinegar

an aqueous solution which contains ethanoic acid

functional group of ester

coo

what are esters

volatile compounds with distinctive smells and are used as food flavourings and in perfumes

what is condensation polymerisation and what does it produce

dicarboxylic acid reacts with diol to produce polyester and water

what polyesters are biodegradable

biopolyesters