Question #a30bd

1 Answer
Apr 24, 2017

#1.61 * 10^23# molecules of water.


This is a very simple chemistry question, and the explanation is as followed:

First, you want to calculate the molar mass of water. You can get the necessary information from the atomic weight of each element (see on the periodic table).
H2O = #(2 * 1.01) + 16 = 18.02 g / (mol)#

Now that you have found the molar mass, continue using dimensional analysis to find the answer. Also, note that I use the number #6.022 * 10^23 (atms)/(mol)#. This is Avogadro's number, and it will be very useful in chemistry.

#4.83 g ((1mol)/(18.02g))((6.022*10^23 atms)/(1 mol))#

All you have to do is plug this into your calculator, and you get
#1.61 * 10^23 # molecules of water in 4.83 g with three significant figures.