Search SchoolNGR

Chemistry Past Questions and Answers

Waec Chemistry Questions

Question 81:

The following are s-block elements except

SchoolNGR Classroom

A Lithium
B Magnesium
C Potassium
D Calcium
E Aluminium

View Answer & Explanation

Question 82:

Which of the following statements is not true of tin? it

SchoolNGR Classroom

A Is a p-block element
B Is extracted from cassiterite SnO ₂
C Is used for protecting iron containers from corrosion
D Combines with copper to form the alloy brass
E Shows two oxidation states, + 2 and + 4 in most of its compounds

View Answer & Explanation

Question 83:

What quantity of copper will be deposited by the same quantity of electricity that deposited 9.0g of aluminum? (A = 27, Cu = 64)

SchoolNGR Classroom

A 64g
B 32g
C 7.1g
D 6.4g
E 3.2g

View Answer & Explanation

Question 84:

The electronic configuration of two atoms X and Y are as follows: X - 1s ² 2s ²2p ⁶3s ¹, Y -1s ²2s ²2p ⁶3s²3p ⁶4s ² which of the statements below is true of the position of X and Y in the Periodic Table?

SchoolNGR Classroom

A X belongs to group 1, Y belongs to period 2,
B X belongs to group 1, Y belongs to period 4
C X belongs to group 2, Y belongs to period 1
D X belongs to group 3, Y belongs to period 2
E X belongs to group 3, Y belongs to period 4

View Answer & Explanation

Question 85:

Which of the following is a condition for a spontaneous reaction?

SchoolNGR Classroom

A âˆ†H -T is zero
B ∆H-T∆ S is positive
C âˆ†H-Tâˆ† S is negative
D âˆ†S is zero
E âˆ†S is positive

View Answer & Explanation

Stay Updated

Follow us on:

Subjects