(a) Explain briefly why \(_2^4He\) has a stable electron configuration compared to \(_4^9Be\) (b) Consider...
(a) Explain briefly why \(_2^4He\) has a stable electron configuration compared to \(_4^9Be\)
(b) Consider the following elements: 1H and 3Li.
(i) State the number of electrons that an atom of each element would have after forming an ionic bond.
(ii) Give a reason for each of your answers stated in (b)(i).
(c) Statetwo factors that should be considered when siting a chemical industry.
(d) Statetwo advantages of using a catalyst instead of high temperatures in chemical reactions.
(e) Turpentine burns in chlorine according to the following equation:
C\(_{10}\)H\(_{16}\)\(_{(I)}\) + 8Cl\(_{2(g)}\) \(\to\) 10C\(_{(s)}\) + 16HCl\(_{(g)}\)
Calculate the mass of turpentine that would completely burn in 21.3 g of chlorine.
[Molar mass of chlorine = 71 gmol\(^{-1}\); Molar mass of Turpentine = 136 gmol\(^{-1}\)]
(f) What is cracking?
(g) Statetwo factors that may influence the value of electron affinity.
(h) What are carbohydrates?
(i) Statetwo differences between a simple sugar and starch.
(j) Write an equation to show the dissociation ofeach of the following acids:
(i) H\(_2\)CO\(_3\);
(ii) CH\(_3\)COOH.
Explanation
(a) \(_2^4He\) has its outermost / Valence shell fully filled with electrons / has maximum number of electrons in its outermost shell / duplet thus more stable whereas \(_4^9Be\) has incomplete filled outermost / valence shell hence less stable.
(b) (i) 1H - 2 electrons / zero
3Li - 2 electrons
(ii)1H - it accepts one electron/ donates one electron
3Li - it loses an electronto have a duplet shell
(c) - nearness to raw material / feed stock
- nearness to markets
- labour supply
- transportation
- availability of power supply
- government policy
- away from residential areas
- storage facilities for raw materials
- source of water supply
- conducive climate
(d) - saves money / the plant does not have to operate for long to produce
- reduces energy / reaction proceeds at a much lower temperature
- no undesirable products are formed / catalyst is specific in action
(e) From the equation:
8 moles of Cl\(_2\) reacts with 1 mole turpentine
1 mole of Cl\(_2\) = 71 g
8 moles = 8 x 71
= 568 g
\(\frac{21.3}{568}\)g will react with 21.3 x 136
= 5.1 g
OR
8 moles of Cl\(_2\) reacts with 1 mole turpentine