Chemical Change

Question 1

what charge is the necleus

Answer 1

positive

Question 2

what charge is electrons

Answer 2

negative (-1)

Question 3

what charge is an atom

Answer 3

no overall charge

Question 4

ion

Answer 4

an atom that looses or gains electrons

Question 5

metallic bonding

Answer 5

the force of attraction between free-moving electrons and positive metal ions

Question 6

what charge is neutrons

Answer 6

neutral charge (0)

Question 7

what charge is protons

Answer 7

positive (+1)

Question 8

ionic bond

Answer 8

force of attraction between oppositely charged ions in a chemical compound

Question 9

ionic compound

Answer 9

a compound held together by a iconic bond

Question 10

exothermic reaction

Answer 10

energy is transferred to the surroundings

Question 11

endothermic reaction

Answer 11

energy is taken in from the surroundings

Question 12

rate of reaction

Answer 12

how quickly a reaction takes place

Question 13

calculation to work out mean rate of reaction

Answer 13

mean rate of reaction = overall change in a value (eg. product formed or reactants used up) / total time taken for the reaction

Question 14

a salt is produced in what reaction? (2 answers)

Answer 14

a neutralisation reaction (alkali reacting with an acid) or a metal reacting with an acid

Question 15

what state symbol is used to show a solid

Answer 15

s

Question 16

what state symbol is used to show a liquid

Answer 16

l

Question 17

what state symbol is used to show a gas

Answer 17

g

Question 18

what state symbol is used to show something that is ‘aqueous’ (dissolved in water)

Answer 18

aq

Question 19

decomposition reaction

Answer 19

the process or effect of simplifying a single chemical entity into two or more fragments

Question 20

reversible reaction

Answer 20

a reaction that can go both backwards and forwards (can be reversed)

Question 21

equilibrium

Answer 21

state in which both the reactants and products are present in concentrations which have no further tendency to change with time

Question 22

dynamic equilibrium

Answer 22

when the forward and reverse processes occur at the same rate and is undergoing constant change, resulting in no observable change in the system