Aim: How can we convert moles? Do Now: Take out a calculator and reference tables. What is Avogadro’s number?

Avogadro’s Number A unit of measurement that states that 1mole (abbreviated 1mol) of a substance is equal to 6.02 x 1023 particles. If it is a gas, 1 mol takes up 22.4 liters of volume. How can we use that information? We can convert between moles and other units of measurement. We can also calculate the number of molecules in a given amount of sample.

Finding the mass of a mole The mass of 1 mole of a substance is essentially the same as the gram molecular mass. It is expressed as grams/mol. Example: What is the mass of 1 mol of K2CO3? Example: What is the mass of 2 mol of H2O?

Converting grams to moles Again - The gram formula mass of any substance is equal to 1 mole of that substance. To convert grams to moles: moles=number of grams x Example: How many moles are there in 4.0g of NaOH? 1 mol gram formula mass

Converting moles to grams The following formula is used: grams = number of moles x Example: How many grams are there in 40.5 mol of H2SO4? gram formula mass 1 mol

Converting moles to molecules If we need to know how many molecules are in a sample, we simply have to remember Avogadro’s number (__________) and multiply accordingly. Example: How many molecules are in 1 mol of H2O? Example: How many molecules are in 2 mol of H2O?

Converting molecules to moles Again- We have to remember Avogadro’s number _____________________ but this time we have to divide. Example: How many moles are in 12.04 x 1023 molecules? Example: How many moles are in 18.06 x 1023 molecules?

Converting moles to Liters This will apply to gas questions. We have to remember that 1 mole of a gas occupies 22.4 liters. Example: How many liters will 2.5 moles of H2 occupy? Example: How many moles are in 67.2 liters of O2?

Activity/Homework Copy and answer questions 27-36 on pages 50-51 in your review book.