Molarity, Dilutions and Preparation of Solutions Lab Exam Review

Glassware needed to prepare stock solution and dilution

Volumetric flask, volumetric pipette and funnel

equation used to calculate the concentration of a diluted solution

Molarity (M) = moles of solute (mol) / volume of solution (L) and M1V1=M2V2

Calculating the concentration of the stock solution

1. grams to moles using molar mass

2. ml to L by dividing by 1000

3. use molarity formula

Calculating the diluted solution

M1 (Stock) V1 (Volume) = M2 (Dilution) V2 (Volume)

Spectrophotometer

used to measure how much a solution absorbs light by measuring the intensity of light as a beam of light passes through the sample at a certain wavelength.

Beer’s Law

describes the relationship between Absorbance and Concentration of the solution.

The Beer law equation

A (absorbance) = ebc

e 

molar absorptivity, a constant that depends on the sample

b

sample cell path length

c

molar concentration of sample

with standard curve y=mx

y = absorbance, mx = eb, x = molar concentration of sample

the experiment’s objectives

Prepare a calibration curve from dilute CuSO4 solutions, determine molar concentration of a dilute solution and an unknown solution using serial dilution

Anhydrous copper sulfate, CuSO₄

potentially harmful, irritating and very toxic to aquatic life.

the wavelength of absorption used in the lab

625 nm

Magnesium oxide can be discarded

into the Solid Inorganic Compounds

Zinc Chloride residue should be discard by

dissolving in ~10 mL water and discarding into the Aqueous Metal Solutions