VERIFIED QUESTIONS AND ANSWERS||
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LATEST UPDATE 2026
What is the test and observation used to identify halide ions (Cl-, Br-, l-)? -
ANSWER-Halide ions in solution react with silver nitrate in the presence of
dilute nitric acid to produce precipitates; Silver chloride is white, Silver bromide
is cream and silver iodide is yellow
What is the test and observation used to identify sulfate ions (SO42-)? -
ANSWER-Sulfate ions produce a white precipitate with barium chloride in the
presence of dilute hydrochloric acid
What are the advantages of using instrumental methods to identify elements and
compounds over chemical tests? - ANSWER-More accurate, more sensitive
(can use smaller sample size) and more rapid
What is flame emission spectroscopy used for? - ANSWER-To analyse metal
ions in solutions
Describe how flame spectroscopy takes place - ANSWER-Sample is put in a
flame and the light given out is analysed through a spectroscope
What is the output of flame emission spectroscopy? - ANSWER-A line
spectrum
,What can you analyse from a flame emission line spectrum? - ANSWER-The
identify and concentration of the metal ions present in solution
For how long has the proportions of the different gases in the atmosphere
remained much the same? - ANSWER-200 million years
What is the composition of today's atmosphere? - ANSWER-Approximately
80% Nitrogen, approximately 20% oxygen and small proportions of various
other gases, including carbon dioxide, water vapour and noble gases
Why do we not know the composition of the Earth's early atmosphere? -
ANSWER-Evidence is limited because of the time scale of 4.6 billion years
What does one theory suggest formed the main atmosphere in the first billion
years of the earth's existence? - ANSWER-Intense volcanic activity releasing
carbon dioxide, water vapour and little or no oxygen into the atmosphere
What are the advantages of extracting copper using phytomining or
bioleaching? - ANSWER-These methods avoid traditional mining methods of
digging, moving and disposing of large amounts of rock
Describe the phytomining process of copper extraction - ANSWER-Plants are
used to absorb metal compounds, harvested and burnt to produce ash that
contains the metal compounds
Describe the bioleaching process of copper extraction - ANSWER-Bacteria are
used to produce leachate solutions that contain metal compounds
How is copper obtained from the products of phytomining or bioleaching? -
ANSWER-By displacement of copper from solutions of copper compounds
using scrap iron or electrolysis
, Why are life cycle assessments carried out on products? - ANSWER-To assess
the environmental impact of a manufactured product during all stages in its life
What are the four stages assessed for a Life Cycle Assessment? - ANSWER-
Extracting and processing of raw materials, manufacturing and packaging, use
and operation during its lifetime and disposal at the end of useful life (including
transport and distribution at each stage)
Which resources is it easy to quantify during life cycle assessment? -
ANSWER-Allocating numerical values to the use of water, resources, energy
resources and the production of some waste materials
Which activities is it not easy to quantify during life cycle assessment? -
ANSWER-Allocating numerical values to the effects of pollutants is not
straightforward and requires value judgements
Name three ways of reducing the use of limited resources - ANSWER-
Reduction in use of products made from limited resources, reuse of products
and recycling of materials from products
Name five materials produced from limited raw materials - ANSWER-Metals,
glass, building materials, clay ceramics and most plastics
Describe how glass bottles can be reused - ANSWER-Glass bottles are crushed
and melted to made into different glass products
Describe how metals are recycled - ANSWER-Metals are melted and recast or
reformed into different products