Chemistry: Stoichiometry & Dimensional Analysis for Equivalent Measures & Calculations, Lecture notes of Stoichiometry

Download Chemistry: Stoichiometry & Dimensional Analysis for Equivalent Measures & Calculations and more Lecture notes Stoichiometry in PDF only on Docsity!

The Mathematics of

Chemistry

Stoichiometry

Dimensional Analysis

Stoichiometry

• (^) Stoichiometry - area of chemistry dealing with the amounts of reactants and products involved in chemical reactions
• (^) Greek root words:
  • (^) stoicheion for element
  • (^) metron for measure

What is the relationship?

• (^) Dimensional analysis is a strategy

used for performing stoichiometric

calculations.

What are some common equivalent measurements?

• (^) 1 inch =______centimeter(s)
• (^) 1 week = ______ day(s)
• (^) 60 seconds = ______minute(s)
• (^) 1 lb =______ ounce(s)
• (^) 1 cup = _____ fluid ounces
• (^) 1 tablespoon = _____ teaspoon(s)
• (^) 4 quarts = _____ gallon(s)

Dimensional Analysis – The Plan

1. What is given? Start your calculation with this quantity with units.
2. What is your goal? What you are solving for is your goal and should be on top of the last step of the problem.
3. Set up a series of equivalent measures that cancels out all units except the goal units.
4. Solve the problem, and remember to mark through the cancelled units.
5. Record the appropriate answer with units.

Give it a try! How many seconds are there in 5.5 days? Follow the steps:

1. What is given? 5.5 days
2. What is your goal, and what are the units? Determine the # of seconds in 5.5 days.
3. Set up a series of equivalent measure that cancels out all units except the goal units. Getting started: **What fractions “equal to 1” help transition from days to seconds?

What are some common equivalent measurements in chemistry?

• (^) 1,000 g = _____kg
• (^) 100 cm = ______ m
• (^) 1 m = _____dm
• (^) 1 L = _____ml
• (^) 1 mole = _______ particles/atoms
• (^) molar mass = _____ mole(s)
• (^) Avogadro’s number = _____ mole(s)

Mole equivalents

MOLE

P A R T I C L E S

G

R

A

M

S

Avogadro’s Number Molar Mass

Molar Mass The mass in grams of 1 mole of the compound calcium carbonate CaCO 3 Ca 1 X 40.078 grams = 40.078 grams C 1 X 12.011 grams = 12.011 grams O 3 X 15.999 grams = 47.997 grams TOTAL = *100.086 grams *Remember the significant figures rules.

Give it a try!

• (^) How many grams are in 4. moles of calcium carbonate?

Give it a try! Stoichiometric Calculations

Chemical Equations

• (^) Recipe for a chemical reaction
• (^) Relative number of reactants and products
  • (^) Coefficients represent the relative numbers.

CH

4

+ 2O

2

 CO

2

+ 2H

2

O

Balancing Chemical Equations C 2

H

5 OH (l) + O 2 (g)  CO 2 (g) + H 2 O (g) Count Atoms: Carbon 2 (^) Carbon 1 Hydrogen 6 Hydrogen 2 Oxygen 3 Oxygen 3

Balancing Chemical Equations C 2

H

5 OH (l) + O 2 (g)  CO 2 (g) + H 2 O (g) C 2

H

5 OH (l) + 3 O 2 (g)  2 CO 2 (g) + 3 H 2 O (g)