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STOICHIOMETRY

Expected Outcomes

Define it! stoi·chi·om·e·try [stòykee ómmətree]

1. The branch of chemistry concerned with measuring the proportions of elements that combine during chemical reactions

2. Quantitative study of reactants and products that take part in a chemical reaction

STOICHIOMETRY

STOICHIOMETRYMore!

STOICHIOMETRYImagine

Ethyl butyrateCH3CH2CH2COOCH2CH3

10 g butyric acidCH3CH2CH2-COOH

to expect?WhatGiven : Amount of reactants Question: how much of products can be formed.

Example

2 A + 2B --------> 3CGiven 20.0 grams of A and sufficient B, how many grams of C can be produced?

How can we measure HOW MUCH?

You can measure mass, or volume,

or you can count pieces.We measure mass in grams.

We measure volume in liters.

We count pieces in…MOLES

MOLEthe

CONCEPT

MOLEthe

CONCEPT

MOLEOne mole of a substance contains the same number of molecules/atoms as in 12 grams of carbon-12.

This number (of atoms or molecules) is known as the Avogadro constant (NA) which is equal to 6.02 x 1023

6.02 x 1023

Carbon 12 atoms 12 grams

1Mole

MOLE

the

CONCEPT

How big is 6 x 1023?Imagine the whole of the United states

You are here!

How big is 6 x 1023?Imagine the whole of the United states covered in unpopped popcorn

How big is 6 x 1023?Imagine the whole of the United states covered in unpopped popcorn to a depth of six miles!

How big is 6 x 1023?Imagine the whole of the United states covered in unpopped popcorn to a depth of six miles!

Count the grains and that is 6 x 1023!

600000000000000000000000

MOLEMore about…

MOLE

CONCEPT

Let’s Practice...

Let’s Practice...

MOLEMore about…

Homework

Coming up next…

Calculating Average Atomic Masses