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(a) (i) Identify the general class of compounds represented by the formula Cₓ(H₂O)ᵧ - HSC - SSCE Chemistry - Question 34 - 2003 - Paper 1
Question 34
(a) (i) Identify the general class of compounds represented by the formula Cₓ(H₂O)ᵧ. (ii) Describe TWO tests that can be used to distinguish between some of the fol... show full transcript
Worked Solution & Example Answer:(a) (i) Identify the general class of compounds represented by the formula Cₓ(H₂O)ᵧ - HSC - SSCE Chemistry - Question 34 - 2003 - Paper 1
Step 1
Step 2
Describe TWO tests that can be used to distinguish between some of the following classes of organic compounds: alkanes, alkenes, alcohols, alkanonic acids.
Answer
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Bromine Test: Alkenes can be distinguished from alkanes by adding bromine water. Alkenes will decolorize bromine water, while alkanes will not.
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Sodium Bicarbonate Test: Alcohols can be identified using sodium bicarbonate solution. When an alcohol reacts with sodium bicarbonate, it will produce carbon dioxide bubbles if it is a primary or secondary alcohol, indicating its presence.
Step 3
Describe ONE precaution you took to minimise hazards, or to dispose of reactants and products safely.
Answer
One precaution taken to minimise hazards was wearing safety goggles and gloves throughout the experiment to prevent any chemical splashes from coming into contact with my skin or eyes.
Step 4
Outline the procedure you used to distinguish between reducing and non-reducing sugars.
Answer
To distinguish between reducing and non-reducing sugars, a sample of each sugar was heated with Benedict's reagent. Reducing sugars will cause the solution to change color to red or orange due to the formation of a precipitate, whereas non-reducing sugars will not react unless they are first hydrolyzed by heating with dilute acid.
Step 5
Analyse how emission spectra of elements assist in the identification of the origins of a mixture.
Answer
Emission spectra provide a unique 'fingerprint' for each element present in a mixture. When elements are heated or energized, they emit light at specific wavelengths, resulting in a spectrum. By analyzing these spectra, one can identify the presence of certain elements, helping to determine the mixture's origins based on the known signatures of elements.