Question

calculate the no of molecules in 1.8 g of h20

Answer 1

!! Hey Mate !!

your answer is ---

Firstly , we find the molar mass of H2O

H2O = 1×2 + 16 = 16+2 = 18

so, 1mole H2O = 18 g

=> 1 g = 1/18 mole H2O

=> 1.8g = 1/18×1.8 mole H2O

=> 1.8g = 0.1 mole H2O


hence , 0.1 mole in 1.8 gram of H2O


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【 Hope it helps you】
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Answer 2

molecular mass of h20 is
2×1+16=18 g

$18 \: g \: contain \: 6.022 \times {10}^{23} \\ so \: 1.8 \: g \: will \: contain \\ 1.8 \times 6.022 \times {10}^{23} \div 18 = \\ = 6.022 \times {10}^{22}$