(a) (i) Define the term Avogadro’s number.
(ii) If 2.30 g of an oxide of nitrogen, x, contains 3.01 x 10\(^{22}\) molecules, calculate the molar mass of x.
(iii) Deduce the formula of x. N, =6.02 x 10″, N =14.0, O = 16.0]
(b)(i) Describe briefly what happens when each of the following substances are added to water:
(I) CCI\(_{4}\); (II) SiCI\(_{4}\),
(ii) Explain briefly why the reactions in (a)(i), (b)(i), (I) and (b)(ii) (II) are different Study the diagram below and answer the questions that follow.
(c) Study the diagram below and answer the questions that follow.
(i) What is the set up used for?
Explanation
(a)(i) This can be defined as the number of atoms or molecules in one mole of a substance which is equal to 6.02 x 10\(^{23}\)
(ii) Mass/m.m = no. of molecules / Avogadro's number
(2.30 / m.m) x (3.01x10\(^{22}\) / 6.02 x 10\(^{23}\))
m.m = (2.30 x 6.02 x 10\(^{23}\)) / 3.01 x 10\(^{22}\)
m.m = 46g / mol
\(\therefore\) 14+('16 x 2)
14 + 32 = 46g /mol
\(\therefore\) No\(_{2}\)
(b)(i) I. Two layers are formed / no reaction / immiscible
II. there is a reaction / hydrolysis with steamy fumes /white fumes
(ii) The reaction occurs by interaction of the tones pair of electrons of water binding to the central atom (silicon or carbon) / attaching to the central atom In silicon, the 3p - orbital is available to accept the pairs of electrons but in carbon, there is no vacant orbitals for bonding.
OR
Water is polar hence the reaction with SiCI\(_{4}\). But CCI\(_{4}\) is non-polar hence there is no reaction
(c) (i) - Purification of metals/ copper
- Electroplating