exam topic 11,12,13

Question 1

the student claimed that it was not necessary to find the value for the C=C bond as they could use the value for a C-C bond and multiply it by 2 explain why she is incorrect

Answer 1

1. include calculation
2. C=C double bonds have both sigma and pi bonds whereas C-C has only sigma bonds so the double bond has a lower bond enthalpy than single carbon-carbon as the electrostatic attraction between the nuclei and shared pair of electrons are weaker in pi bonds than in sigma bonds

Question 2

Explain in terms of entropy why the combustion of prop-2-ene-1-ol is always feasible in the gaseous state

Answer 2

when it combusts to its gaseos state it has the highest entropy as entropy increases to a maximum therefore the entropy change is positive and large so it is feasible

Question 3

Describe what effect if any increasing the pressure would have on the equilibrium constant kp justify your answer

Answer 3

to be done

Question 4

Explain the effect of this on the yield of ammonia by considering the change in the kc expression and hence the position of the equilibrium

Answer 4

to be done

Question 5

small amounts of sodium hydroxide and hydrochloric acid are added to separate samples of the buffer solution explain why these samples resist changes in PH and illustrate your answer with at least two equations

Answer 5

to be done