How many particles are represented by 22.9g H2O?

Answer 1

Always start with what you are given. In this case, we are given 22.9 g of H2O. Keep in mind what units you are given initially and what units you would like to end with, always.

We are given 22.9 grams and we are tasked to find particles, which can also be referred to as molecules.

To make it easier to understand, set up dimensional analysis and have your units cross out until you get to particles. Units cross out when they are on opposite sides of each other. For instance:

22.9 g of H20 * (1 mol of H20 )/ (18.016 g of H2O) * (6.022 x 10^23 particles of H2O)/ ( 1 mol of H2O)

To make sure you do not get the wrong number when using dimensional analysis, multiply the entire top row ( 22.9 g * 1 mol* 6.022 x 10^23 particles), multiply the entire bottom row ( 18.016 g* 1 mol), and then divide the products by each other.

The answer you get is 7.65 x 10^23 particles.

1. Where did I get 18.016 g of H2O?

This is the molar mass of water, where you need to multiply the molar masses of each element inside H2O to get the total molar mass. For example, hydrogen has a molar mass of 1.008 and there are 2 hydrogens, and oxygen has a molar mass of 16.00 and there is 1 oxygen. So, (1.008*2)+(16*1), you get 18.016.

This is necessary for the dimensional analysis because we want to make sure we know how many grams are in one mol of H2O at all times. If we are given 22.9 g of H2O, we use this base value of 18.016 g per mol of water to find the mols in the given amount.

Then, in each mol of water, there is ALWAYS 6.022 x 10^23 molecules/particles. This is Avogadro's Number, which you should memorize for whenever you need to find molecules/particles of any substance.

Answer 2

Question: How many particles are represented by 22.9g of H2O (water)?

Answer:

To determine the number of particles in 22.9 grams of water, we follow these steps:

1. Calculate the Molar Mass of H2O: The molar mass of water (H2O) is calculated by adding the atomic masses of its constituent atoms. For H2O, which consists of 2 hydrogen atoms and 1 oxygen atom:
2. Molar mass of Hydrogen (H) = 1.008 g/mol (for each hydrogen atom).
3. Molar mass of Oxygen (O) = 16.00 g/mol.
4. Total molar mass of H2O = 2 * 1.008 + 16.00 = 18.016 g/mol.
5. Convert the Mass of H2O to Moles: The number of moles of H2O is found by dividing the mass of the water by its molar mass.
6. Moles of H2O = Mass of H2O / Molar Mass of H2O = 22.9 g / 18.016 g/mol.
7. Use Avogadro's Number: Avogadro's number, which is approximately 6.022 x 10^23, represents the number of particles in one mole of a substance. To find the total number of particles in the given mass of water, multiply the number of moles by Avogadro's number.

After performing the calculations, the number of particles in 22.9 grams of water is found to be approximately 7.65 x 10^23 particles. This illustrates the large number of molecules present in a seemingly small quantity of water.