Chemistry P2 June

Question 1

Bond energy

Answer 1

Energy needed to break chemical bnds to form neutral atoms

Question 2

Bond length

Answer 2

the average distance between the nuclei of two bonded atoms

Question 3

Ionic bonding

Answer 3

Electrostatic interaction between cation and anions that involves the transfer of electrons and forms a three dimensional lattice structure

Question 4

covalent bonding

Answer 4

electrostatic interaction that involves the sharing of electrons between atoms to form molecules

Question 5

dative covalent bonding

Answer 5

bond that involves the sharing of an electron pair between atoms where both electrons are donated by one of the two atoms

Question 6

molecule

Answer 6

neutral group of two or more atoms chemically bonded together which act as a single unit in chemical reactions

Question 7

electronegativity

Answer 7

the tendency of an atom to attract a shared pair of electrons towards itself

Question 8

heat of a reaction

Answer 8

energy absorbed or released in a chemical reaction

Question 9

exothermic reaction

Answer 9

reaction that releases energy

Question 10

endothermic

Answer 10

reaction that absorbs energy

Question 11

reversible reaction

Answer 11

products can be converted back into reactants

Question 12

activation energy

Answer 12

minimum energy needed for a reaction to take place

Question 13

activated complex

Answer 13

unstable transition state from reactants to products in a chemical reaction

Question 14

positive catalyst

Answer 14

substance that increases the rate of a chemical reaction without itself undergoing a permanent change

Question 15

boiling point

Answer 15

constant temperature at which th vapour pressure of a substance equals atmospheric pressure

Question 16

melting point

Answer 16

the temperature at which the solid and liquid phases of a substance are at equilibrium

Question 17

vapour pressure

Answer 17

pressure exerted by a vapour at equilibrium with its liquid in a closed system

Question 18

forces of cohesion

Answer 18

forces of attraction between molecules of the same substance

Question 19

forces of adhesion

Answer 19

forrces of attraction between molecules of different substances

Question 20

capillarity

Answer 20

the tendency of a liquid to be elevated or depressed in a narow tube as a result of surface tension

Question 21

capillarity

Answer 21

the tendency of a liquid to be elevated or depressed in a narow tube as a result of surface tension

Question 22

one mole

Answer 22

amount of substance having the same number of particles as there are atoms in 12g carbon-12

Question 23

dipole dipole force

Answer 23

force between polar molecules

Question 24

london forces (dispersion forces)

Answer 24

forces between non polar molecules

Question 25

limiting reagent

Answer 25

the reagent which is used up first during a chemical reaction