Chemistry Past Questions And Answers
Sieving is a technique used to separate mixture containing solid particles of
- A. small sizes
- B. large sizes
- C. differents sizes
- D. the same sizes
In the Periodic Table, the elements that lose electrons most readily belong to
- A) group IA
- B) group IIA
- C) group IIIA
- D) group VIIA
Consider the reaction represented by the equation:23892U +10n→13656Ba +9436Kr + 310n. The reaction represents a
- A. nuclear fission
- B. nuclear fusion
- C. radioactive decay
- D. spontaneous disintegration
Tartaric acid is used industrially to
- A) make baking powder
- B) make fruit juices
- C) remove rust
- D) dry substance
The type of energy changes that accompany the mixing of a strong acid to a strong base is
- A. electrical
- B. heat
- C. light
- D. sound
Before a reaction could take place, there should be
- A. ionization of reactant particles
- B. breakage of bonds of products
- C. breakage of bonds of reactants
- D. ionization of product particles
A sample of a gas exerts a pressure of 8.2 atm when confined in a 2.93 dm3 container at 20°C. The number of moles of gas in the sample is? (R = 0.082 litre atm / deg mole)
- A. 1.00
- B. 2.00
- C. 3.00
- D. 4.00
Which of the following pairs of substances will react further with oxygen to form a higher oxide?
- A) CO2 and H2O
- B) NO and H2O
- C) CO and CO2
- D) SO2and NO
(a)(i) Define hard water
(ii) Name two substances responsible for hardness in water
(iii) Give two methods for the removal of hardness in water.
(b)(i) What are the raw materials require for the manufacture of tetraoxosulphate (VI) acid by the contact process?
(ii) Write an equation for tr reaction that requires a catalyst in the contact process (iii) State the catalyst used in (b)(ii).
(c)(i) Give two uses of sodium tetraoxosulphate (VI) Consider the reaction represented by the following equation:
Na\(_2\)SO\(_4\).10H\(_2\)O\(_{(s)}\) \(\to\) Na\(_2\)SO\(_4\).H\(_2\)O + 9H\(_2\)O\(_{(g)}\)
(ii) What name is given to this type of reaction?
(iii) Calculate the solubility of Na\(_2\)CO\(_3\) at 25°C. if 30.0 cm\(^3\) of its saturated solution at that temperature gave 1.80 g of the anhydrous salt. [C = 12, 0 = 16, Na = 23]
(d)(i) Define the term activated complex
(ii) State one reason why a collision may not produce a chemical reaction
(iii) The formation of water gas is represented by the following equation:
C\(_{(s)}\) + H\(_2\)O\(_{(g)}\) \(\to\) CO\(_{(g)}\) + H\(_{2(0)}\) \(\Delta\)H= + 131 kJmol\(^{-1}\)
Draw an energy profile diagram for the reaction showing the I. activated complex, II. enthalpy of reactants.
View Discussion (0)WAEC 2008 THEORYWhat is the molar mass of a substance, if 0.4 mole of the substance has a mass of 25.0g?
- A. 62.5 g
- B. 40.0 g
- C. 6.3 g
- D. 2.5 g