A group 2 metal, M, is reacted with water so that M + 2H2O --> M(OH)2 + H2. 0.162g of metal produces 97.0cm3 of gas at RTP. Identify M.
1 mole of gas is produces for 1 mole of metal used.
n (moles) = volume/24000 ---- This is because 1 mole of a gas occupies 24000cm3 of space, so it's a simple ratio to work out moles(H2).
= 97/24000
= 0.004042 moles.
For group 2 metal, we want to work out the RFM, so we use:
RFM = grams/moles --- Rearranged from moles = grams/rfm
= 0.162/0.004042
= 40.1 gcm-3
This corresponds to calcium.
CS
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