Unit 1b -Inorganic and Physical Chemistry

Question 1

what does the value of the equilibrium constant indicate

Answer 1

the position of the equilibrium

Question 2

what happens to equilibrium in an exothermic reaction when the temperature is increased

Answer 2

the equilibrium moves to favour the production of the reactants. The yield of products decreases

Question 3

what happens to equilibrium in an endothermic reaction when the temperature is decreased

Answer 3

the equilibrium moves to favour the production of products. The yield of products increases

Question 4

what condition has an impact on the vale of K constant

Answer 4

Temperature

Question 5

what does amphoteric mean and give an example

Answer 5

amphoteric describes a substance which can react as an acid and a base.

an example of this would be water

Question 6

what is an acid

Answer 6

a substance which donates a proton and form a conjugate base

Question 7

what is a base

Answer 7

a substance which accepts a proton and forms a conjugate acid

Question 8

what does the salt of a strong acid and base form in water

Answer 8

a neutral solution

Question 9

what does the salt of a weak acid and strong base form in water

Answer 9

a alkaline solution

Question 10

what does the salt of a strong acid and weak base form in water

Answer 10

an acidic solution

Question 11

what is a buffer

Answer 11

a buffer is a solution of which the pH remains constant when small amounts of acid or base are added

Question 12

what is an acidic buffer

Answer 12

consist of a weak acid and one of its salts

Question 13

what is a basic buffer

Answer 13

consists of a weak base and one of its salts

Question 14

what happens when acid and base are added to acidic buffer

Answer 14

ACID
will react with ions of the salt to be converted back into the salt
BASE
will react with the H+ ions to neutralise and equilibrium will then move to replace the lost H+ ions

Question 15

what happens when acid and base are added to a basic buffer

Answer 15

ACID
will combine with OH- ions to neutralise and equilibrium will move to replace lost OH- ions
BASE
will react with the ions of the salt to be converted back into salt

Question 16

what is an indicator

Answer 16

weak acid which changes colour depending on the pH of the solution,

Question 17

what is the standard state of a substance

Answer 17

1 atmosphere

298 K

Question 18

what is standard enthalpy of formation

Answer 18

the enthalpy change when one mole of a substance is formed from elements in their standard states.

Question 19

what is entropy

Answer 19

measure of the degree of disorder of the system

Question 20

what has the lowest and greatest value of entropy

Answer 20

lowest - solids

greatest - gases

Question 21

what happens to entropy as temperature increased

Answer 21

entropy increases

Question 22

what is the entropy value of a perfect crystal

Answer 22

0K

Question 23

when is a reaction said to be feasible

Answer 23

when the ^G between reactants and products is negative

Question 24

Under non-standard conditions when is a reaction feasible

Answer 24

if ^G is negative

Question 25

what is the value of ^G at equilibrium

Answer 25

0

Question 26

what does the rate of reaction depend on

Answer 26

the concentration of reactants

Question 27

what is zero order reaction

Answer 27

when the rate does not change as the concentration is changed

Question 28

what is a 1st order reaction

Answer 28

when doubling the concentration doubles the rate

Question 29

what is a 2nd order reaction

Answer 29

when doubling the concentration quadruples the rate

Question 30

what is the rate of reaction dependant on

Answer 30

dependant on the slowest step which is called the rate determining step

Question 31

how can the rate of reaction be determined

Answer 31

the rate can only be determined experimentally

Question 32

What happens to the water equilibrium: | NH4Cl - Cl + NH4+

Answer 32

the ammonium ions combine with the OH- ions forming molecules of the weak alkali, ammonium hydroxide. To replace the lost OH- ions the equilibrium moves to the right. This gives an excess of H+ ions resulting in an acidic solution.

Question 33

what happens to the water equilibrium: | CH3COONa - CH3COO- + Na+

Answer 33

ethanoate ions combine with the h+ ions to form molecules of the weak acid, ethanoic acid. To replace lost H+ ions the water equilibrium moves to the right. This produces an excess of OH- ions resulting in an alkaline solution