Jamb Chemistry Past Questions For Year 1989
Question 1
COg + H2Og \(\to\) 2g + H2g \(\Delta\)H = -4100J. Which of the following factors favour the formation of hydrogen in the above reaction? i. high pressure. ii. low pressure iii. high temperature iv. use of excess steam
- A. i, iii and iv
- B. iii only
- C. ii, iii and i
- D. iv only
Question 2
Which of the following would support the conclusion that a solid sample is a mixture?
- A. the solid can be ground to a fine powder
- B. the density of the solid is 2.25 g dm3
- C. the solid has a melting range of 300oC to 375oC
- D. the solid absorbs moisture from the atmosphere
Question 3
The atomic radius of Li, Na and K are 1: 33A, 1. 54A and 1. 96A res pectively. Which of the following explaqins this gradation in atomic radius?
- A. electropositivity decreases from Li to Na to K
- B. electronegativity decreases from Li to Na to K
- C. the number of the electron shells increases from Li to Na to K
- D. the elements are in the same period
Question 4
What is the partial pressure of hydrogen gas collected
over water at standard atmospheric pressure and 25 oC if the saturation vapour pressure of water at saturation vapour pressure of water is 23 mm Hg at that temperature?
- A. 737 mm Hg
- B. 763 mm Hg
- C. 777 mm Hg
- D. 783 mm Hg
Question 5
The minimum volume of oxygen required for the complete combustion of a mixture of 10cm 3 of CO and 15 cm 3 of H 2 is
- A. 25.0cm3
- B. 12.5 cm3
- C. 10.0 cm3
- D. 5.0cm3
