Chemical combination - Jamb Chemistry Past Questions and Answers

Question 146:

• JAMB 2019

The heat of formation of ethene, C\(_2\)H\(_4\) is 50 kJmol\(^{-1}\), and that of ethane, C\(_2\)H\(_6\) is -82kJmol\(^{-1}\). Calculate the heat evolved in the process:
C\(_2\)H\(_4\) + H\(_2\) \(\to\) C\(_2\)H\(_6\)

A. -122kJ
B. -132kJ
C. -88kJ
D. -60kJ

Question 147:

• JAMB 2019

200cm\(^3\) of 0.50mol/dm\(^3\) solution of calcium hydrogen trioxocarbonate (IV) is heated. The maximum weight of solid precipitated is

A. 10g
B. 25g
C. 20g
D. 15g

Question 148:

• JAMB 2020

The number of molecules of Carbon(iv)Oxide produced when 10.0g of CaCO\(_3\) is treated with 0.2dm\(^3\) of 1 Mole of HCL in the equation
CaCO\(_3\) + 2HCL ⇒ CaCl\(_2\) + H\(_2\) O + CO\(_2\) , is ?

A. 1.00 X 10\(^{23}\)
B. 6.02 X 10\(^{23}\)
C. 6.02 X 10\(^{22}\)
D. 6.02 X 10\(^{24}\)

Question 149:

• JAMB 2020

A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?
[ M = 27, Cl = 35.5]

A. MCl
B. MCl\(_2\)
C. MCl\(_3\)
D. M\(_2\)Cl\(_6\)

Question 150:

• JAMB 2021

The metal used to recover copper from a solution of copper sulphate is?

A. Na
B. Ag
C. Hg
D. Fe