INTRODUCTION TO SOLUTIONS/ACIDS AND BASES

HONORS CHEMISTRY

MAY 27TH, 2014

WHAT IS A SOLUTION?

A solution is a homogenous mixture of to or more substances.

The most common solutions are aqueous solutions, those with a solid, liquid, or gas in water.

A solution has at least two components:

- Solvent: The majority component

- Solute: The minority component

CONCENTRATION

The amount of solute in a solution is an important property of a solution.

A dilute solution contains small amounts of solute relative to solvent.

A concentrated solution contains large amounts of solute relative to solvent.

MOLARITY

Molarity (M) is a way to express solution concentration.

Molarity is defined as the number of moles of solute per liter of solution.

PREPARING A SOLUTIONNote that molarity is moles of solute/liters of solution, not solvent. To make a solution of a specific molarity, you usually put the solute into a flask and then add water to desired volume of solution.

PRACTICE PROBLEMS!

Calculate the molarity of a solution made by putting 15.5 g of NaCl into a beaker and adding water to make 1.50L of NaCl solution.

DILUTION EQUATION

M1V1 = M2V2 Where…

- M1 and V1 are the molarity and volume of the initial

concentrated solution

- M2 and V2 are the molarity and volume of the final diluted

solution

PRACTICE PROBLEM

To what volume should you dilute 0.100 L of a 15 M NaOH solution to obtain a 1.0 M NaOH solution?

SOLUTION STOICHIOMETRY Many chemical reactions take place in aqueous solutions. We know from stoichiometry that coefficients in chemical equations are conversion factors between moles of reactants and moles of products.

PRACTICE PROBLEM!

How much 0.125 M NaOH solution do we need to completely neutralize 0.225 L of 0.175 M H2SO4 solution?