4.5 Stoichiometry

The term used to describe conversions involving mole ratios from a balanced chemical equation

Stoichiometry

When doing stoichiometry, you must start with a:

Balanced chemical equation

Starting with a balanced chemical equation when doing stoichiometry will ensure that:

Atoms and mass are conserved

Is every stoichiometry question the same?

No

When doing stoichiometry, it is imperative to:

Read the problem to determine what you are being asked to find out and what you already know

Why is it imperative to read the problem to determine what you are being asked to find out and what you already know when doing stoichiometry?

Every stoichiometry problem is different

When doing stoichiometry, the coefficients from the balanced equation will be used to create the:

Mole ratio

Mole ratio allows for the:

Conversion between the quantities given in the problem and quantities of other materials that you want to find out about

The term “stoichiometric ratio” means that:

The ratio of moles in the problem matches the ratio in the balanced equation

Could you be given information about more than one of the reactants?

Yes

When you are given information about more than one of the reactants, it signals that:

You will have a limiting reagent in the problem

The reactant that runs out first

Limiting reagent

The reactant that is not completely consumed

Excess reagent

How to determine amount of product produced when dealing with limiting reagents?

Consider how much product each reacting particle can produce separately, and then compare the values, reporting the answer that produces the least

Might the predicted amount of product be produced in a lab situation?

No

How to calculate percent yield?

Actual yield over theoretical yield times 100%

Often the actual yield is same/different from the theoretical yield

Different

Is it normal for the actual yield to be different from the theoretical yield?

Yes

In the lab the goal is to:

Get your actual yield as close as possible to the theoretical yield

The term to describe how much you should be able to make based on the amounts given in the problem

Theoretical yield

Theoretical yield is also called:

Predicted value or calculated mass

The term to describe the amount that you actually make in the experiment

Actual yield

Actual yield is also called:

Experimental yield or actual mass obtained

A way to describe how close your experimental yield was to the amount predicted

Percent yield

How to convert from mass to moles?

Use molar mass

How to convert from liters of gas at stp to moles?

Use molar volume of gas

How to convert liters of solution to moles?

Use molarity

How to convert from particles to moles?

Use avogadro’s number

How many particles in one mole?

6.02×10^(23)

How much volume of 1 mole of gas at stp?

22.4 L

Unit of molarity:

Moles / L

Molar mass is calculated using:

Periodic table and chemical formula