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 AVERAGE

ATOMIC MASSATOMIC MASS

Because of isotopes, the mass of a collection of Because of isotopes, the mass of a collection of atoms has an average value.atoms has an average value.

Boron is 20% Boron is 20% 1010B and 80% B and 80% 1111B. That is, B. That is, 1111B is B is 80 percent of Boron on earth. 80 percent of Boron on earth.

For boron atomic weightFor boron atomic weight

= 0.20 (10 amu) + 0.80 (11 amu) = 10.8 amu= 0.20 (10 amu) + 0.80 (11 amu) = 10.8 amu

10B

11B

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 1023 particles

1 mole C = 6.02 x 1023 C atoms

1 mole H2O= 6.02 x 1023 H2O molecules

1 mole NaCl= 6.02 x 1023 Na+ ions and

6.02 x 1023 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 CaCl2 = 111.1 g/mole

2 moles N x 14.0 g/mole + 4 moles O x 16.0 g/mole

1 mole of N2O4 = 74.0 g/mole

Molar Mass of Compounds

12

A. 1 mole of K2O = ______g

B. 1 mole of antacid Al(OH)3 = ______g

Learning Check

13

A. 1 mole of K2O = 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 + Cl2 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 + Cl2 2 NaCl

5 mol Na 1 mol Cl2

2 mol Na= 2.5 moles Cl2

Mole-Mole Conversions

2 Na + Cl2 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 H2 + O2 2 H2O

How many moles of O2 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?