Chemistry – Apr 9, 2019 P3 Challenge – Get out Empirical Formula Worksheet for HMK check P3 Challenge – Determine the Empirical Formal for a compound that contains 24.741% potassium, 34.764% manganese and 40.496% oxygen. Today’s Objective – Moles and Chemical formulas Agenda Hmk Review Pair vs Pair competition Moles and Chemical formulas (time permitting) Assignment: Chemical Formula Worksheet

Homework Ans. only 1. 28.45% Cu 71.55% Br 2. 57.48 % Na 40.00% O 2.52% H 3. 41.11 % N 11.83 % H 47.05 % S 4. 30.41 % N 69.59 % S 5. 24.74 % K 34.76 % Mn 40.50 % O 6. 2.76 % H 97.24 % Cl 7. 16.39 % Mg 18.89 % N 64.72 % O 8. 28.19 % N 8.11 % H 42.92 % O 20.78 % P 9. 15.77 % Al 28.11 % S 56.12 % O 10. FeSO3 iron(II) sulfite 11. CrCl3 chromium (III) chloride 12. TlC2H3O2 Thallium (I) acetate 13. ZnO Zinc oxide 14. C5H3O2N2 15. C4H5ON2 C8H10O2N4 16. HO H2O2 17. O3C3N3Cl3 18. C5H7N C10H14N2

Practice in teams of 2-3 Create problem for another team using a worksheet. (to be handed in) Pick a compound. (Keep it a secret from your other team.) Determine the molar mass of your compound. Find the percentage of elements in your compound. (Double check for accuracy) Exchange your lists of a) molar mass, b) elements, c) mass percents on P3 paper Determine your mystery compound Convert your list of percents and molar mass to a chemical formula. Check your answer with your challengers Turn in your P3 paper questions and answers complete with your names and the names of your challengers.

Chemical Formulas and Conversion Factors Because the chemical formula indicates the number and ratio of atoms in a compound, conversion factors can be written to convert between moles of atoms and moles of compounds. Ex: 1 mole CO2 contains 1 mole of C and 2 mole of O Ex: How many moles of O are present in 3.25 mol of H3PO4?

Gram – mole –number of items problems Grams of X Moles of Y Grams of Y Moles of X Not Here!! Molar mass Chemical formula Number of X Number of Y 6.022x1023 Atomic scale Macroscopic scale Liters of X 22.4

Gram – mole problems using the chemical formula Grams of CO2 Ex: Determine the number of moles of CO2 in a 15.0 g sample of CO2. Ex: What mass does 1.25 moles of CO2 have? Molar mass 44.01 g/mol Moles of CO2

Gram – mole problems using the chemical formula Moles of CO2 Moles of C or O Ex: Determine the number of moles of C in 8.30 mole of CO2. Ex: Determine the number of moles of O in 0.592 mole of CO2.

Gram – mole problems using the chemical formula Grams of CO2 Ex: Determine the number of moles of C in 15.0 g of CO2. Ex: Determine the number of moles of O in 15.0 g of CO2 Molar mass 44.01 g/mol Moles of CO2 Chemical formula Moles of C or O

Gram – mole problems using the chemical formula Grams of CO2 Grams of C, O Molar mass 44.01 g/mol Molar mass 12.01 g/mol, 16.00 g/mol Chemical formula Moles of CO2 Moles of C, O Ex: Determine the number of grams of a)carbon and b)oxygen in 22.75 g of CO2.

Gram – mole – number problems using a chemical formula Grams of X How many copper atoms are present in a 1.688 gram sample of copper (I) oxide, Cu2O? Molar mass 143.09 g/mol Moles of X Chemical formula Moles of Y Macroscopic scale Atomic scale Number of Y

Gram – mole –number of items problems Grams of X Moles of Y Grams of Y Moles of X Not Here!! Molar mass Chemical formula Number of X Number of Y 6.022x1023 Atomic scale Macroscopic scale Liters of X 22.4

Exit Slip - Homework Exit Slip: How many grams of silver are present in 23.5 g of silver nitrate? What’s Due? (Pending assignments to complete.) Chemical Formula worksheet What’s Next? (How to prepare for the next day) Read p100-102, p224-232, 241 p246-247