Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 1271: A certain industrial process is represented by the chemical equation 2A_(g) + B_(g) $\to$ C_(g) + 3D_(g) $\mathrm{\Delta }$H = X kJmol^-1. Which of the following conditions will favour the yield of the products? Options:
  A) increase in temperature, decrease in pressure
  B) increase in temperature, increase in pressure
  C) decrease in temperature,increase in pressure
  D) decrease in temperature, decrease in pressure
  E) constant in temperature, increase in pressure
  Show Answer
  The correct answer is A .
• Question 1272: In countries where the temperature falls below 273K, salt is always sprinkled on the icy road in order to Options:
  A) lower the melting point of the ice
  B) increase the density of the ice
  C) make the ice impure
  D) raise the melting point of the ice
  Show Answer
  The correct answer is A .
• Question 1273:

  

  The compound above contains

  Options:
  A) Sp ³ hybridized carbon atoms only
  B) Sp ² hybridized carbon atoms only
  C) Sp ³ and Sp hybirdized carbon atoms
  D) Sp ³ and Sp ²
  Show Answer
  The correct answer is D .
• Question 1274: A noble gas with a high power of fog penetration used in aerodrome beacons is Options:
  A) krpton
  B) argon
  C) helium
  D) neon
  Show Answer
  The correct answer is D .
• Question 1275: The line observed in the sample hydrogen spectrum are due to emission of? Options:
  A) electrons from the atoms
  B) energy by proton transition
  C) energy by electron transition
  D) neutron from the atom
  Show Answer
  The correct answer is C .
• Question 1276: In the oil drop experiment, Millikan determined the? Options:
  A) charge to mass ratio of the electron
  B) mass of the electron
  C) charge of the electron
  D) mass of the proton
  Show Answer
  The correct answer is C .
• Question 1277:

  What are the possible oxidation numbers of an element if its atomic number is 17?

  Options:
  A) -1 and 7
  B) -1 and 6
  C) -3 and 5
  D) -2 and 6
  Show Answer
  The correct answer is A .
• Question 1278: A burning candle produces water and Options:
  A) Carbon (II) oxide
  B) Carbon (IV) oxide
  C) Oxygen
  D) Hydrogen
  Show Answer
  The correct answer is B .
• Question 1279:

  An organic compound contains 69% carbon, 15.3% hydrogen and 30.7% oxygen. Calculate the the empirical formula [C=12, H = 1, O = 16]

  Options:
  A) C${}_4$H${}_{1}2$O
  B) C${}_3$H${}_9$O
  C) C${}_4$H${}_9$O
  D) C${}_3$H${}_8$O
  Show Answer
  The correct answer is D .
• Question 1280:

  What unit of temperature should be used when applying the ideal gas law?

  Options:
  A) Fahrenheit (°F)
  B) Kelvin (K)
  C) Rankine (°R)
  D) Celsius (°C)
  Show Answer
  The correct answer is B .