Chemistry Past Questions and Answers

A reaction takes places spontaneously if?

A âˆ†G = O
B ∆S < O and ∆H > O
C âˆ†H < T âˆ†S
D âˆ†G > O

Question 22:

The standard enthalpies of formation of CO_2(g), H₂O(g) and CO_(g) in kJ mol^- are -394, -242 and -110 respectively. What is the standard enthalpy change for the reaction CO_(g) + H_2(g)O â†’ CO_2(g) + H_2(g)?

A -42 KJ mol^-
B +42 KJ mol^-
C -262 KJ mol^-
D +262 KJ mol^-

Question 23:

10g of a solid is in equilibrium with its own vapour.
When 1 g of a small amount of solid is added, the vapour pressure?

A Remains the same
B Drops
C Increases by 1%
D Increases by 99%

Question 24:

NaCI_(s) + H₂SO_4(I) â†’ HCI_(g) + NaHSO_4(s).
In the reaction above, H₂SO₄ behaves as?

A A strong acid
B An oxidizing agent
C A good solvent
D A dehydrating agent

Question 25:

Which of these gases can be dried with concentrated H2SO4?

A HBr
B H₂S
C NH₃
D SO₂