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secondary 4 | A Maths
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why is it C and not D
Date Posted: 3 years ago
Views: 373
Maybe when they meant "air", they meant "the outside air".
Because NH3 is the lightest and it's the only gas of the four which is less dense than air, the NH3 gas will escape when the lids are removed (I assume it's from the top).
Taking its place is the heavier air from the surroundings.
Because NH3 is the lightest and it's the only gas of the four which is less dense than air, the NH3 gas will escape when the lids are removed (I assume it's from the top).
Taking its place is the heavier air from the surroundings.
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done
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This is a fairly common concept tested for O-level Chemistry and similar to these questions in my book 'Explain That! Chemistry (2nd Ed, 2020)'. Ammonia has a molecular mass of 17, hence is less dense than air. Air (average molecular mass is about 28.6) being denser, displaces ammonia out of the gas jar at the fastest rate (compared to A, nitrogen - molecular mass 28). Hence the answer is C. Oxygen (Mr 32) and S02 (Mr 64) are denser than air and hence will only diffuse out of the gas jar at a slow rate (recall the greater molecular mass of a gas, the slower the diffusion rate).
Date Posted:
3 years ago
thx :)
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