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 781:

  What is the state of matter in which particles are widely spaced and move freely with high kinetic energy?

  Options:
  A) Liquid
  B) Solid
  C) Plasma
  D) Gas
  Show Answer
  The correct answer is D .
• Question 782: Which is the temperature of a given mass of a gas initially at 0°C and 9 atm, if the pressure is reduced to 3 atm at constant volume? Options:
  A) 91K
  B) 182K
  C) 273K
  D) 819K
  Show Answer
  The correct answer is A .
• Question 783: Aluminium hydroxide is used in the dyeing industry as a Options:
  A) dye
  B) dispersant
  C) salt
  D) mordant
  Show Answer
  The correct answer is D .
• Question 784: Which of the following would support the conclusion that a solid sample is a mixture? Options:
  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 300^oC to 375^oC
  D) the solid absorbs moisture from the atmosphere
  Show Answer
  The correct answer is C .
• Question 785: Which of the additives could improve the quality of steel? Options:
  A) Silicon
  B) Sulphur and phosphorus
  C) Carbon
  D) Chromium and nickel
  Show Answer
  The correct answer is D .
• Question 786: What is the formula of sodium gallate if gallium (Ga)shows an oxidation number of + 3? Options:
  A) NaGaO₃
  B) Na₂Ga(OH)₃
  C) NaGa(OH)₃
  D) NaGa(OH)₄
  E) NaGaO
  Show Answer
  The correct answer is D .
• Question 787:

  

  Use the graph above to answer this question.

  A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section PQ indicates that X is

  Options:
  A) a mixture of salts
  B) a hydrated salt
  C) an ionic salt
  D) a pure compound
  Show Answer
  The correct answer is D .
• Question 788:

  Which of the following substances is NOT hygroscopic?

  Options:
  A) Salt
  B) Sugar
  C) Silica gel
  D) Aluminum
  Show Answer
  The correct answer is D .
• Question 789: Under high pressure, real gases do not obey gas laws because their molecules? Options:
  A) have become more energetic
  B) have become less energetic
  C) have become smaller in size
  D) decompose into atoms
  E) start repelling each other
  Show Answer
  The correct answer is B .
• Question 790:

  Duralumin consists of aluminum, copper?

  Options:
  A) Zinc and Gold
  B) Lead and Manganese
  C) Nickel and Silver
  D) Manganese and Magnesium
  Show Answer
  The correct answer is D .