SAT2化學真題一道what is the approximate molarity of water?

題目：

SAT2化學真題一道
what is the approximate molarity of water?

解答：

1 liter of water is 1000g,one mol of water weighs 18g,so each liter has
1000(g/L)/(18g/mol)
= 55.5 mol/L
= 55.5M