Equal masses of CH4 and O2 are mixed. The average molar mass of the mixture is (C = 12, H = 1, O = 16)

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Equal masses of $CH X_{4}$ and $O X_{2}$ are mixed. The average molar mass of the mixture is (C = 12, H = 1, O = 16)

A $24.00 g mo l^{- 1}$
B $21.33 g mo l^{- 1}$
C $22.40 g mo l^{- 1}$
D $20.00 g mo l^{- 1}$

Answer: B

Take 1 g of each: moles = 1/16 + 1/32 = 0.09375. Average M = total mass/total moles = 2/0.09375 = 21.33 g/mol. The simple mean 24 is wrong because the mixture is by mass, not by moles.

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Equal masses of CHX4​ and OX2​ are mixed. The average molar mass of the mixture is (C = 12, H = 1, O = 16)

Answer: B

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Equal masses of $CH X_{4}$ and $O X_{2}$ are mixed. The average molar mass of the mixture is (C = 12, H = 1, O = 16)