1. 7.3

2. Formula Mass – for any molecule, formula unit, or ion, it is the ____ of the ________ masses of all atoms represented in its formula. H 2 O for example is H = 1.008 x 2 = 2.016 amu O = 15.999 x 1 = 15.999 amu Total = 18.015 amu

3. Try to find the mass of KClO 3 H 2 SO 4 Ca(NO 3 ) 2 PO 4 3- MgCl 2

4. The mass of 1 mol of a substance in g/mol H 2 O for example is H = 1.008 x 2 = 2.016 g/mol O = 15.999 x 1 = 15.999 g/mol Total = 18.015 g/mol The ___ mass is numerically = to the ___ mass

5. You can convert grams to moles and vice versa using ______ ______ You can also convert atoms to moles and vice versa using ___________ #

6. What is the mass in grams of 2.50 mol of oxygen gas? How many moles are in 100 g of H 2 O? How many moles are in 10 grams of Carbon? molecules of CH 4 ? How many moles are in 3.01 x 10 23 molecules of CH 4 ? How many atoms are in 15 moles of S? How many atoms are in 15 moles of S?

7. How many molecules are there in the following… 25.0 g H 2 SO 4 125 g Sugar C 6 H 12 O 6 How many grams are in… 6.5 x 10 23 atoms of Cu 5.12 x 10 30 molecules of CH 4

8. Percent Composition – the % by mass of each _________ in a cmpd To calculate % Comp, determine _______ mass of entire compound. Calculate the % of each element by __________ the mass of each ___________ by the molar mass.

9. Determine the percent composition of Al and O in Al 2 O 3. Determine the composition of Al, S, and O in Al 2 (SO 4 ) 3

10. Find the % comp of each element in the following PbCl 2 Ba(NO 3 ) 2 Find the % water in ZnSO47H 2 O Mg(OH) 2 is 54.87% O by mass. How many g of O are in 175 g of the cmpd? How many moles of O is this?

11. Complete the section review on page 244 numbers 1-6. This is due at the beginning of class tomorrow!