The smaller number is the number of atoms of the element to the left of it. No number means one atom. For CO2 there is one atom of carbon and

**two atoms**of oxygen. For H2O, there is one atom of oxygen and**two atoms**of hydrogen.Keeping this in view, how many molecules are in a glass of water?

A mole is defined as Avogadro's number of particles of any kind of substance (atoms,

**molecules**, or ions). Avogadro's number is approximately 6.022 × 10^{23}. Thus 18.01508 grams of**water**contain 6.022 × 10^{23}**water molecules**. A**glass**of**water**, or 200 grams of**water**, therefore contains 6.6855 × 10^{24}**water molecules**.How many molecules are in a mole of water?

If you have a compound like H

_{2}O, then: one mole of water contains**6.02**x**10**of water. But each molecule of water contains 2 H and 1 O atom = 3 atoms, so there are approximately 1.8 x 10^{23}MOLECULES^{24}atoms in a mole of water.How many molecules are in a gallon of water?

A "mole" of water weighs about 18 grams and has ~

**6.02**x10^**23 molecules**. There are**3785.4118**grams of water per gallon, so there are 3.22x10^-19 gallons in**41,000,000 molecules**of water