Question

convert into mole 20 gram of water

Answer 1

we know the molecular mass of hydrogen is 1 and oxygen is 16.

we know the formula of water is H2O

H2O
=2×1+16
= 2+16
= 18g
So, one mole of water weight is 18g.

therefore no of mole = give mass/molar mass

so, 20/18 = 1.11 moles

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Answer 2

$given \: mass \: of \:water = 20g \\ molar \: mass \: of \: water = 2 \times atomic \: mass \: of \: h + atomic \: mass \: of \: o \\ 2 \times 1 + 16 = 2 + 16 \\ = 18 \\ therefore \: no \: of \: moles \: = \frac{given \: mass}{molar \: mass} \\ = \frac{20}{18} \\ = 1.11moles$
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