1 1. Which of the following statements is most accurate based on the data in this chart? A.Sunlight does not affect the growth of tomato plants. B.Tomato plants will grow more slowly with decreasing amounts of sunlight. C.Tomato plants grow most rapidly when exposed to less sunlight. D.There is no correlation between growth rate and amount of sunlight. 2. Assume that one of the factors below had been used in this experiment. Which one would not have altered the outcome of the experiment? A.Fertilizer was used on Tray 3. B.Tray 1 was watered every day, while Trays 2&3 were watered every other day. C.Each Tray was given different soil. D.Each student took turns tending the plants. Objective:Convert between the moles and grams of a substance. Catalyst 11/3/10 Please have out homework to check. Four students conducted an experiment to test how sunlight affects plant growth. They planted 3 trays of tomatoes and measured the height of plants over a period of 25 days. Tray 1 was kept in full sunlight for the duration of each day, Tray 2 was kept in sunlight only half of the day and Tray 3 was kept in sunlight for only 3 hours each day.

Agenda Isotopes & atomic mass (10) Molar mass (20) Mole to mole conversions (15) Homework: Molar mass and mole to mole conversion problems 2

Atoms of the same element that differ in mass. (They have the same # of p +, but different # of N°) ISOTOPE

The periodic table has masses with decimals because it gives the average atomic mass of all of the isotopes

AVERAGE ATOMIC MASS Because of isotopes, the mass of a collection of atoms has an average value. Because of isotopes, the mass of a collection of atoms has an average value. Boron is 20% 10 B and 80% 11 B. That is, 11 B is 80 percent of Boron on earth. Boron is 20% 10 B and 80% 11 B. That is, 11 B is 80 percent of Boron on earth. For boron atomic weight For boron atomic weight = 0.20 (10 amu) (11 amu) = 10.8 amu = 0.20 (10 amu) (11 amu) = 10.8 amu 10 B 11 B

6 1 trio= 3 singers 1 six-pack Cola=6 cans Cola drink 1 dozen donuts=12 donuts 1 gross of pencils=144 pencils Collection Terms

7 Contains 6.02 x particles 1 mole C = 6.02 x C atoms 1 mole H 2 O= 6.02 x H 2 O molecules 1 mole NaCl= 6.02 x Na + ions and 6.02 x Cl – ions A Moles of Particles

8 Number of grams in 1 mole Equal to the numerical value of the atomic mass 1 mole of C atoms= 12.0 g 1 mole of Mg atoms =24.3 g 1 mole of Cu atoms =63.5 g Molar Mass

9 Give the molar mass to 0.1 g A. 1 mole of Br atoms =________ B.1 mole of Sn atoms =________ Learning Check

10 Give the molar mass to 0.1 g A. 1 mole of Br atoms =79.9 g/mole B.1 mole of Sn atoms =118.7 g/mole Solution

11 Mass in grams of 1 mole equal numerically to the sum of the atomic masses 1 mole Ca x 40.1 g/mole + 2 moles Cl x 35.5 g/mole 1 mole of CaCl 2 = g/mole 2 moles N x 14.0 g/mole + 4 moles O x 16.0 g/mole 1 mole of N 2 O 4 = 74.0 g/mole Molar Mass of Compounds

12 A. 1 mole of K 2 O = ______g B. 1 mole of antacid Al(OH) 3 = ______g Learning Check

13 A. 1 mole of K 2 O= 94.2 g 2 K x 39.1 g/mole + 1 O x 16.0 g/mole B. 1 mole of antacid Al(OH) 3 = 78.0 g 1 Al x 27.0 g/mole + 3 O x 16.0 g/mole + 3 x 1.0 Solution

Cookies and Chemistry…Huh!?!? Just like cookies have recipes, chemicals have recipes as well-we call them chemical equations Instead of using cups, we use moles Instead of eggs, butter, sugar, etc. we use chemical compounds as ingredients

Chemistry Recipes A reaction tells us how much of something you need to react with something Example: 2 Na + Cl 2  2 NaCl This reaction tells us that by mixing 2 moles of sodium with 1 mole of chlorine we will get 2 moles of sodium chloride. What if we wanted 4 moles of NaCl? 10 moles? 50 moles?

Mole Ratios Mole ratios can be used to calculate the moles of one chemical from the given amount of a different chemical Example: How many moles of chlorine are needed to react with 5 moles of sodium (without any sodium left over)? 2 Na + Cl 2  2 NaCl 5 mol Na 1 mol Cl 2 2 mol Na = 2.5 moles Cl 2

Mole-Mole Conversions 2 Na + Cl 2  2 NaCl How many moles of sodium chloride will be produced if you react 2.6 moles of chlorine gas with an excess (more than you need) of sodium metal?

Practice 2 H 2 + O 2  2 H 2 O How many moles of O 2 would we need if we wanted 4 moles of water? If we had 3 moles of oxygen, how much hydrogen would we need to react, and how much water would we get? What if we had 50 moles of hydrogen, how much oxygen would we need, and how much water would be produced?