FORMULA MATH & THE MOLE

1. FORMULA MATH & THE MOLE

2. The Mole Measuring Matter

3. In Chemistry, we commonly measure: • Mass (grams) • Volume (L or mL) • Particles (counted)

4. We can relate each of these measurements to a single quantity called the “Mole”.

5. The Mole is the SI unit for the “amount of something”

6. Why use it? • To estimate the number of particles that are too small or too numerous to actually count.

7. 1.0 mole = 22.4 Liters of a gas, at standard temperature and pressure (STP) • Std. temp. = 0º C or 273K • Std. pressure = 1 atmosphere (atm) or 760 mm Hg (Torr)

8. 1 mole = 6.022 x 1023particles of a pure substance. * Element = atom * Molecular = molecule (mlc) *Ionic = formula unit (fmu)

9. 1.0 mole = ____ grams of a pure substance. (“Molar Mass” of that substance)

10. Molar Mass – mass, in grams, of 1 mole of a pure substance.

11. What is the Molar Mass of: • Carbon tetrachloride

12. Oxygen

13. Aluminum carbonate

14. Calculating with Moles

15. Remember…. 1 mole = 6.022 x 1023 particles = 22.4 liters of gas, at STP ______ grams (Molar Mass)

16. Steps to calculate: READ directions in Lecture Packet.

17. Example What is the mass of 45.8 L of carbon dioxide gas, at STP?

18. Example: How many moles are equal to 3.01 x 10 22 atoms of magnesium?

19. Example: How many molecules are in 38.69 grams of chlorine gas?

20. Example: What is the volume, in L, at STP, occupied by 0.600 moles of sulfur dioxide gas?

21. Comparing amounts • 1 mole CCl4 = • 6.022 x 1023 molecules • _153.81_ grams • Liters is N/A (not a gas)

22. Comparing amounts • 1 mole O2 = • 6.022 x 1023 molecules • _32.00_ grams • 22.4 Liters, at STP

23. Comparing amounts • 1 mole Al2(CO3)3 = • 6.022 x 1023 formula units • _233.99_ grams • Liters is N/A (not a gas)

24. How big is a Mole? • If you have a mole of pennies and divide them equally among the 6 billion people on Earth, how many dollars would each person get?

25. = $1x1012 person x 1$ 100 pennies 6.022 X1023 pennies 6 x 109 people Each person would get ~ $ 1 trillion!!!

26. Percent Composition

27. Think about it... What is the percent composition of the number of boys to girls in this classroom?

28. Now, think about this... What is the percent composition of the weight of boys to girls in this classroom?

29. In Chemistry, it’s calculated the same way, except we consider the make-up of compounds.

30. What information does % Composition give us? The percent, by mass, of each element in a compound.

31. Formula: grams element ------------------------ X 100 = % grams compound

32. 2 Ways To Calculate: 1) Chemical Formula is given 2) Masses are given (no formula given)

33. If formula is given: • Write chemical formula. • Count atoms of each element in compound. • Multiply by Mass Number from P.T.(round all mass # to the 10th). • Add answers. • Plug numbers into formula and solve.

34. Example #1 What is the percent composition of water?

35. Example#2 What is the % composition of aluminum chromate?

36. If masses are given: 1) g element + g element g compound *Remember the Law Of Conservation Of Mass

37. Example#3 What is the percent composition of a compound if 27.07 grams of calcium completely reacts with 47.93 grams of chlorine?

38. More Formula Math!!!

39. Empirical Formula • The simplest whole number ratio of elements in a compound. • Cannot be reduced.

40. Molecular Formula • the actual number of atoms of each element present in a substance. • Is a wholenumbermultiple of the E.F. • Can be reduced.

41. From the “mole” perspective… Ba3N2 Al2(SO4)3

42. C6H12O6 H2O2

43. To calculate Empirical Formulas: READ directions in your LECTURE PACKET!

44. example… What is the E.F. of a compound composed of 32.00% Carbon, 42.66% Oxygen, 18.67% Nitrogen, and 6.67% Hydrogen?

46. example… What is the E. F. of a compound composed of 25.9% Nitrogen and 74.1% Oxygen?

48. example… What is the E. F. of a compound composed of 36.6 grams of Carbon and 9.2 grams of Hydrogen?

50. To calculate Molecular Formulas: READ direction in LECTURE PACKET!!!