In chemistry the unit we use to measure the “amount of a substance” is the mole The mole can be related to the # of particles (molecules or atoms), the mass, or the volume of an element or compound

How do we determine the mass of 1 mole of any element? The mass of that element off the periodic table in grams 1 mol C = 1 mol Ca = 1 mol N = 1 mol W =

How do you think we determine the mass of one mole of a compound? The formula of a compound tells you the # of atoms of each element in the compound. You can calculate the mass by adding together the atomic masses of each element in the compound 1 mol NaCl = g g = g 1 mol CO 2 = g + 2(16.00 g) = g

Molar mass  refers to the mass of a mole of any element or compound. (Use your periodic table)

1 mol Ra = 1 mol Li = 1 mol CH 4 = 1 mol CaF 2 = 1 mol C 12 H 22 O 11 = 1 mol H 2 O = 1 mol (NH 4 ) 2 SO 4 =

Working in groups of two complete activity #2 You will need your masses from Activity #1 Make sure to show work for one example problem PART B: Use four different substances Masses of the containers are on the containers Once you have filled in the data table answer the questions-make sure to show all your work!!!!

1 mole = molar mass of any element or compound (use periodic table) 1 mole = x particles (molecules, atoms, formula units)

1. Determine the molar mass of magnesium bromide. 2. What is the mass of 4.63 moles of magnesium bromide? 3. How many moles would x formula units of magnesium bromide be? 4. Determine the molar mass of Tin. 5. If you have g of Tin how many moles would that be? 6. How many atoms of Tin would the above # of moles be?

DUE MONDAY FEB 2nd Page # 3 Page # 5 and (6-will need two steps) Page #7, 8, 13, and 14 Page #16 and 17 Page # 19 MAKE SURE YOU SHOW YOUR WORK!!!!!

Determine the molar mass for the following substances 1 mol C 4 H 9 O 2 = 1 mol Ca 3 (PO 4 ) 2 = 1 mol AgCl = 1 mol Ca(C 2 H 3 O 2 ) 2 =

Percent composition-the percent by mass of each element in a compound

1. Calculate the molar mass of the compound. 2. Determine the total mass of each element in the compound 3. Divide the mass of one element in the compound by the molar mass of the compound. 4. Multiply answer by 100 to get percentage. 5. Do step 2 for each element in the compound. 6. Add %’s to make sure they = 100%

Calculate the percentages of each element in the following compounds C 3 H 8 C 2 H 6 Ca(C 2 H 3 O 2 ) 2

% by mass of element = mass of element x 100 mass of compound A compound is formed when 9.03 g of Mg combines completely with 3.48 g of N. What is the percent composition of this compound?

Pages 326 and and 36b

What is the percent by mass of nitrogen in Ammonium Hydroxide?

Determine the % Composition of Mg(OH) 2

When g sample of a compound containing only magnesium and oxygen is decomposed, 5.40g of oxygen is obtained. What is the percent composition of this compound?

Read through the procedure and create a data table in your notebook for any data that you will be collecting when doing the lab. Mass of crucible and cover _________g Mass of KClO 3 _________g

Determining the % of each element in an unknown compound % mass of element X = grams of element X x 100 grams of compound

Calculate the % composition of the compounds that are formed from the following reactions g of Ag combine completely with 4.30 g of S.

Using percent composition to calculate the grams of an element in a specific amount of a compound. Based on %’s Mass of compound x mass of element (from %) 100 g compound Because 100%  assume 100 g total That way we can change the % of each element into grams to plug into the equation

Calculate the amount of Hydrogen in 350 g of C 2 H 6. Calculate the amount of Hydrogen in 124 g of Ca(C 2 H 3 O 2 ) 2

Mass of crucible and cover _________g Mass of KClO 3 _________g Mass of crucible, cover and contents after 1 st heating __________g Mass of crucible, cover and contents after 2 nd heating __________g Mass of crucible, cover and contents after 3 rd heating __________g (if needed)

During the heating in step #4 calculate the % composition by mass of the compound potassium chlorate. Step 7 Calculation Mass of oxygen Mass of Compound (started with) x 100

#12 page 150 #13 page 151 #14 page 153

#12 Sodium Selenium Lead #13 C 2 H 6 PCl 3 C 3 H 7 OH N 2 O 5 #14 Sr(CN) 2 NaHCO 3 Al 2 (SO 3 ) 3