1. Warm Up – December 6, 2017
How many electrons are in the outermost energy level of a phosphorus atom?
What is the element symbol for an element with 14 protons?
What is the charge of an atom that has 17 protons and 15 electrons?
What ion has 12 protons and 10 electrons?
If your favorite TV station broadcasts at a frequency of 2.34 x109 Hz, what is the wavelength of the signal in meters?

2. Start the Bubble Gum Lab!

3. EQ: How do I calculate percent composition of a compound?

4. EQ: How do I calculate percent composition of a compound?
What is percent composition?
Percentage of each element found in a compound

5. EQ: How do I calculate percent composition of a compound?
Example: What percent of Iron (III) hydroxide, Fe(OH)3 is oxygen? Step 1: Find the molar mass of the compound Fe = 56 g/mol 56 + (16)(3) + (1)(3) =
O = 16 g/mol
H = 1 g/mol
107 g/mol

6. EQ: How do I calculate percent composition of a compound?
Example: What percent of Iron (III) hydroxide, Fe(OH)3 is oxygen? Step 1: Find the molar mass of the compound Fe(OH)3 = 107 g/mol Step 2: Find the percentage by dividing the part by the whole and multiplying by 100. O = 16 g/mol
48 g
x 100
= 45% O
16 x 3 = 48 g
107 g

7. EQ: How do I calculate percent composition of a compound?
1. What percent of magnesium bromide, MgBr2, is magnesium? Step 1: Find the molar mass of the compound Mg = 24 g/mol 24 + (80)(2) =
Br = 80 g/mol
184 g/mol

8. EQ: How do I calculate percent composition of a compound?
1. What percent of magnesium bromide, MgBr2, is magnesium? Step 1: Find the molar mass of the compound MgBr2 = 184 g/mol Step 2: Find the percentage by dividing the part by the whole and multiplying by 100. Mg = 24 g/mol
24 g
x 100
= 13% Mg
24 x 1 = 24 g
184 g

9. EQ: How do I calculate percent composition of a compound?
2. What percent of glucose, C6H12O6, is carbon? Step 1: Find the molar mass of the compound C = 12 g/mol (12)(6) + (1)(12) + (16)(6) =
H = 1 g/mol
O = 16 g/mol
180 g/mol

10. EQ: How do I calculate percent composition of a compound?
2. What percent of glucose, C6H12O6, is carbon? Step 1: Find the molar mass of the compound C6H12O6 = 180 g/mol Step 2: Find the percentage by dividing the part by the whole and multiplying by 100. C = 12 g/mol
72 g
x 100
= 40% C
12 x 6 = 72 g
180 g

11. EQ: How do I calculate percent composition of a compound?
3. What percent of Zn3(PO4)2 is zinc? Step 1: Find the molar mass of the compound Zn = 65 g/mol (65)(3) + (31)(2) + (16)(8) =
P = 31 g/mol
O = 16 g/mol
385 g/mol

12. EQ: How do I calculate percent composition of a compound?
3. What percent of Zn3(PO4)2 is zinc? Step 1: Find the molar mass of the compound Zn3(PO4)2 = 385 g/mol Step 2: Find the percentage by dividing the part by the whole and multiplying by 100. Zn = 65 g/mol
195 g
x 100
= 51% Zn
65 x 3 = 195 g
385 g

13. EQ: How do I calculate percent composition of a compound?
4. An 8.20-g piece of magnesium combines completely with 5.40 g of oxygen to form a compound. What is the percent composition of each element in this compound?
To the board!

14. EQ: How do I calculate percent composition of a compound?
5. Which has a higher percent of aluminum, Al2O3 or Al(NO3) 3?
To the board!