In the redox reaction represented by the following equation: Cu^{2+_aq + Zn_(s) → Cu_(s) + Zn2+}

A. the oxidation number of copper increases

B. copper (ll) ions are reduced to copper atoms

C. zinc atoms are reduced to zinc ions

D. copper (ll) ions donate electrons to zinc atoms

When starch undergoes complete enzyme-catalyzed hydrolysis, the resulting product is

A. glucose

B. maltose

C. sucrose

D. fructose

E. cellulose

Which of the reactions represented by the following equations will take place at room temperature?

A. C 6 H₂O → CO + H₂

B. CuO + H₂ → Cu + H₂O

C. N₂ + 3H₂ → 2NH₃

D. 2Na + 2H₂O → 2NaOH + H₂

E. 2Fe + 3CI₂ → 2FeCI₃

Which of the following is not a direct petroleum product?

A. Methane

B. Ethanol

C. Petrol

D. Vaseline

E. Kerosene

How many principal electronic shells has an atom whose electronic configuration is shown below? 1s²2s²2p⁶3s¹

A. 1

B. 2

C. 3

D. 4

E. 11

Which of the following properties is not characteristic of electrovalent compounds?

A. formation of crystalline solids

B. solubility in polar solvents

C. high vapour pressures

D. high melting and boiling points

E. ability to conduct electricity in aqueous solution

Compounds that have the same molecular formula but different structures are said to be

A. allotropic

B. polymorphic

C. polymeric

D. isomeric

E. isotopic

In which of the following crystals are the particles held by van der Waal's forces only?

A. Sodium chloride

B. Ice

C. Diamond

D. Iodine

E. Quartz

A current of 4.0 amperes was passed through copper (ll) tetraoxosulphate (IV) solution for one hour using copper electrodes. What was the mass of copper deposited? (Cu = 64, 1F = 96500 C)

A. 3.2g

B. 4.8g

C. 6.4g

D. 48g

E. 96g

When a crystal was added to its solution, it did not dissolve and the solution remained unchanged, showing that the solution was

A. concentrated

B. supersaturated

C. unsaturated

D. colloidal

E. saturated