Chemistry Molarity Lab Sheet 4-23-12
*Materials
- solid NaCl
- water
- 50mL volumetric flask
- electronic balance
Procedure
- Measure the mass of a clean, dry volumetric flask.
- Add 30-35g of NaCl to the flask.
- Measure the mass of the flask again
- Half fill the flask with tap water and shake it gently until all the NaCl has been
dissolved.
- Fill the flask with water to the 50mL mark and measure the mass again.
- Create a data table to record these results. (no I won’t help you with the table! I am
quite certain you can construct one yourself…)
Analyze: Enter the following equations into your SIS then use the data from your table
above to answer the following questions….
1. % by mass tells how many grams of solute are present in 100g of solution.
Equation: % by mass = mass of solute
mass of solute + solvent (mass of solution)
**Calculate the % by mass of NaCl in the solution
2. Mole fraction tells how many moles of solute are present for every 1mol of total
solution.
Equation:
mole fraction = mol NaCl
mol NaCl + mol H2O
**Calculate the mole fraction of your solution
3. Molality tells how many moles of solute are present in 1kg of solvent
Equation:
molality (m) =
mol NaCl
kg of H2O
**calculate the molality of your solution
4. Molarity (M) tells how many moles of solute are dissolved in 1L of solution.
Equation: molarity (M) = mol NaCl
L of solution
**Calculate the molality of your NaCl solution
5. Density tells how many grams of solution are present in 1mL of solution
Equation:
density = g of solution
mL of solution
**Calculate the density of your solution