Science Practice Quiz 9

Q1.In the reaction between sodium sulphate and barium chloride, the white substance formed, barium sulphate, has which of the following characteristics?

A. It is highly soluble in water. B. It is insoluble in water. C. It is a gas at room temperature. D. It is a liquid at room temperature.

Q2.What is observed when copper powder is heated in a china dish?

A. It turns brown. B. It becomes coated with black copper(II) oxide. C. It melts into a liquid. D. It evaporates completely.

Q3.In a chemical reaction, a substance is said to be oxidised if it performs which of the following actions?

A. Loses oxygen. B. Gains hydrogen. C. Gains oxygen. D. Loses electrons.

Q4.What happens to a substance if it is said to be reduced during a chemical reaction?

A. It gains oxygen. B. It loses oxygen. C. It gains hydrogen. D. It loses electrons.

Q5.Consider the reaction: CuO + H₂ → Cu + H₂O. Which substance is oxidised in this reaction?

A. CuO B. H₂ C. Cu D. H₂O

Q6.What is the term for chemical reactions in which one reactant gets oxidised while the other gets reduced?

A. Double displacement reactions B. Decomposition reactions C. Redox reactions D. Combination reactions

Q7.When hydrogen gas is passed over heated black copper(II) oxide, what is the observed change and product formed?

A. The coating turns blue, forming copper hydroxide. B. The coating turns brown, forming copper. C. The coating turns white, forming copper carbonate. D. The coating remains black, forming copper sulfide.

Q8.Which type of chemical reaction involves an exchange of ions between the reactants?

A. Redox reactions B. Combination reactions C. Decomposition reactions D. Double displacement reactions

Q9.In a double displacement reaction involving the formation of BaSO₄ precipitate, which other product typically remains in the solution?

A. Potassium iodide B. Lead(II) nitrate C. Sodium chloride D. Copper(II) oxide

Q10.What is the primary reason for balancing a chemical equation?

A. To represent the physical states of reactants and products symbolically. B. To ensure the number of atoms of each type is the same on both reactant and product sides. C. To identify whether the reaction is exothermic or endothermic. D. To determine if the reaction is a combination or decomposition type.

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Science Practice Quiz 9