Question

Total Number of Hydrogen atoms in 27g of Water is
a) 1.8066 × 10^24 b) 1.2044 × 10^24
c) 1.8066 × 10^23 d) 1.80066 × 10^25

Answer 1

Water has a molar mass of #18.01528 \ "g/mol" ~~ 18 \ "g/mol"#.

So, in #18 \ "g"# of water, there will be

#(18cancel"g")/(18cancel"g""/mol")=1 \ "mol"#

Since water has a chemical formula of #H_2O#, there will be #2# moles of hydrogen in every mole of water.

In one mole of water, there will exist approximately #6.02*10^23# water molecules.

So, there will be a total of #6.02*10^23*2~~1.2*10^24# hydrogen atoms.