1. (a ) Define the term compound.
(b) State two conditions necessary for the cracking of petroleum fractions.
(c) Name two transition elements that are used as catalyst.
(d) (i) Write an equation for the reaction between zinc dust and trioxonitrate (V) solution.
(ii) Which of the reactants in 1(d)(i) is:
I. reduced;
II. oxidized.
(e) Two isotopes of oxygen 16O and 18O have relative abundance of 90 % and 10 % respectively. Calculate the relative atomic mass of oxygen.
(f) List two ores of iron.
(g) (i) What is biotechnology?
(ii) Name one product that can be obtained using biotechnology.
(h) Define the term element.
(i) State two sources of methane in the atmosphere.
(j) Explain briefly why the trend of the boiling points for group VII elements is in the order I\(_2\) > Brl\(_2\)> Cl\(_2\).
Explanation
(a) A compound is defined as a substance containing two or more elements / different atoms chemically combined (in a fixed proportion by mass)
(b) - high temperature
- catalyst
- high pressure
(c)- Iron
- Nickel
- Palladium
- Platinium
- Rhodium
(d)(i) Zn(s) + 2AgNO\(_3\)(aq) → Zn(NO\(_3\))\(_{2(aq)}\) + 2 Ag(s)
(ii) I. AgNO\(_3\) / Ag + is reduced
II. Zn is oxidized
(e) \(\frac{16}{8}\)O = 90%, \(\frac{18}{8}\)O = 10%
Relative atomic mass = \(\frac{\frac{16 \times 90}{199} + \frac{18 \times 10}{100} }{(16 \times 0.9) + (18 \times 0.1)}\)
= \(\frac{1440}{100} + \frac{180}{100}\)
= 14.4 + 1.8
= 16.2
(f) - haematite (Fe\(_2\)O\(_3\))/ Iron (III) oxide
- magnetite (Fe\(_3\)O\(_4\))/Iron (II) Iron (III) oxide
- limonite Fe\(_2\)O\(_3\).nH\(_2\)O/Iron (III) oxide hydrate(accept FeO(OH).nH\(_2\)O)
- iron pyrites FeS/Iron (II) Sulphide
- Siderite/spathic iron ore /FeCO\(_3\)/Iron (II) trioxocarbonate (IV)
(g) (i) It is the use of biological processes / organisms / system to manufacture
useful products
(ii) - garri, fufu, kenkey, bread
- bio-gas,
- alcoholic beverages (beer, whisky, burukutu, gin, etc)
- drugs (vaccines, hormonal, antibiotics)
- enzymes
- biodegradable plastics
- pests control
- organic fertilizers
(h) An element is defined as a substance containing only one type of atom / substance which
cannot be broken down into a simpler one.
(i) - land fill sites / compost
- marshes/swampy area
- rice (paddy) fields
- bacteria
- natural gas
- biomass burning
- crude oil/petroleum
- decay of organic matter
- raising of livestock
- coal mine
(j) The molecules are held together by van der Waal’s forces . The larger the atom, the greater the van der Waal’s forces/increase in molecular mass and hence the higher the boiling point.