When a few drops of water is added to a blue anhydrous cobalt (II) chloride, the colour changes to

• A) white
• B) pink
• C) red
• D) blue

The oxidation number of oxygen in BaO₂ is

• A) -2
• B) -4
• C) -1
• D) 0

(a)The table below gives the volume/pressure data for a particular sample of a gas-at a given temperature.

(i) Deduce a mathematical relationship between volume (V) and pressure (P).

(ii) Name law that can be deduced from the data.

(iii) Calculate the pressure of the gas when the volume is 3.20 dm\(^3\)

(b)(i) What is the role of a salt bridge in an electrochemical cell?

(ii) What type of ions must flow into the cathode? Give a reason for your answer.

(iii)A standard galvanic cell constructed with Ag\(^+_{(aq)}\) Ag\(_{(s)}\) and Zn\(^{2+}_{(aq)}\) couple is discharged until 3.3 g of Ag forms.

I. Write the overall cell reaction and standard cell potential?

II. How many moles of electrons flowed through the circuit during the discharge?

III. How many coulombs of charges flowed through the circuit?

Ag\(^+_{(aq)}\) + e\(^-\) \(\rightleftharpoons\) Ag\(_{(s)}\); E° = + 0.80V

Zn\(^{2+}_{(aq)}\) + 2\(^-\) \(\rightleftharpoons\) Zn\(_{(s)}\), E° = – 0.76 V [Ag = 108]

(c)(i) Define each of the following terms: I. Activation energy; II. Exothermic reaction.

(ii) Give one example of an endothermic process.

(iii) What is the significance of activated complex in a chemical reaction?

Environmental pollution is worsened by the release from the automobile exhaust of

• A) water vapour
• B) steam
• C) smoke
• D) heavy metals

Which of the following properties increases from left to right along the period but decreases down the group in the Periodic Table? I. Atomic Number ii. Ionization energy iii. Metallic character iv. Electron affinity

• A) ii and iii only
• B) ii and iv only
• C) iii and iv only
• D) i and ii only

(a) Give one example of a metal which:

(i) can displace hydrogen from cold water

(ii) at red-heat, reacts reversibly with steam

(iii) does not react with dilute hydrochloric acid

(b) When dry hydrogen was passed over lead (II) oxide, a greyish solid J was obtained.

(i) Identify J

(ii) What type of reaction was involved in the formation of J from lead (II) oxide?

The following substances are normal salts except

• A. AI(NO₃)₃
• B. FeSO₄
• C. Mg(OH)NO₃
• D. NaCI

An iron ore is known to contain 70.0% Fe₂O₃. The obtain from 80kg of the ore is? (Fe = 56, O = 16)

• A. 35.0 kg
• B. 39.2 kg
• C. 70.0 kg
• D. 78.4 kg

Electrons enter into orbitals in order of increasing energy as exemplified by?

• A. 1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^2\)2pz\(^0\)3s\(^0\)
• B. 1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^1\)2pz\(^1\)3s\(^0\)
• C. 1S\(^2\)2S\(^2\)2PX\(^1\)2py\(^1\)2pz\(^1\)3s\(^1\)
• D. 1S\(^2\)2S\(^2\)2PX\(^2\)2py\(^2\)2pz\(^0\)3s\(^1\)

Which organic compound is responsible for the characteristic aroma of fruits?

• A. Alkane
• B. Alkyne
• C. Ester
• D. Amine