definitions

Question 1

moles

Answer 1

same no. of particles there are in 12g of carbon-^12

Question 2

relative atomic mass

Answer 2

weighted average mass of an atom of an element relative to 1/12 the mass of a carbon ^-12

Question 3

empirical

Answer 3

simplest whole number ratio of each element to each other within a compound

Question 4

first ionisation energy

Answer 4

energy required to remove one electron from one mole of an atom to form a unipositive ion

Question 5

ideal gas

Answer 5

a gas that follows kinetic theory of gases

Question 6

co-ordinate bond

Answer 6

covalent bond where both electrons in the bond come from just one of the atoms

Question 7

electronegativity

Answer 7

power of an electron to attract a pair of electrons in a covalent bond towards itself

Question 8

polarity

Answer 8

the unequal sharing of electrons in a bond

Question 9

dipole

Answer 9

difference in charge between two atoms caused by a shift in electron density in the bond

Question 10

periodicity

Answer 10

patterns across a period which are repeated in other periods

Question 11

activation energy

Answer 11

minimum energy required for a successful reaction

Question 12

rate

Answer 12

change in concentration of a product per unit of time

Question 13

catalyst

Answer 13

substance that increases rate of reaction without being used up

Question 14

calorimetry

Answer 14

process of measuring amount of heat released/absorbed during a chemical reaction

Question 15

hess’ law

Answer 15

overall enthalpy change for a reaction that is independent of the route taken

Question 16

nucleophile

Answer 16

electron pair donator

Question 17

electrophile

Answer 17

electron pair accepter

Question 18

disproportionation

Answer 18

when a species is simultaneously oxidised and reduced

Question 19

reduction

Answer 19

gain of electron

Question 20

oxidation

Answer 20

loss of electrons

Question 21

equilibria

Answer 21

reaction where both forward and backwards reactions occur at the same rate, meaning conc of reactants and products remain constant

Question 22

le chateliers principle

Answer 22

whatever change you make to an equilibrium system the system will shift to oppose the change

Question 23

hydration

Answer 23

addition of water

Question 24

biofuel

Answer 24

renewable fuel made from plants

Question 25

enthalpy of formation

Answer 25

overall heat energy change when one mole of a substance is formed from its constituent elements in their standard state

Question 26

enthalpy of combustion

Answer 26

overall heat energy change when one mole of a substance is completely burned in oxygen to form its combustion products