WAEC Chemistry 2018 Theory — Question 12
Question 12 of 24 from the West African Examinations Council (WAEC) Chemistry 2018 Theory paper, with the correct answer and a full explanation.
Advertisement
2.(b)(i) Sketch a graphical representation of Charles' Law. (ii) Calculate the volume of oxygen that would be required for the complete combustion of 2.5moles of ethanol at s.t.p. [molar volume at s.t.p = 22.4dm³]
Model answer
(i) A graph of Volume (V) against Temperature (T in Kelvin) is a straight line passing through the origin (or through −273°C on a Celsius axis). (ii) C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O. 1 mole ethanol requires 3 moles O₂, so 2.5 moles requires 7.5 moles O₂. Volume = 7.5 × 22.4 = 168dm³.
Advertisement
Sign up free to unlock
- Score tracking
- Practice history
- Saved questions
- Progress dashboard
- Personalized sessions
- Weak-topic breakdown
…and/or go further with premium services and No Ads.