Hola

Celia Medina
IB Chemistry 11
2nd Period
November 1, 2012
Conductivity of Solutions
How does the mass of the solute affect the concentration of the solution?

Dependent variable:concentration of the solution
-concentration measured using conductivity
Independent Variable: mass of the solution
-5 different masses
Control Variable: volume and temperature of solution
Volume of solutionwould change the concentration of mixture. Temperature of solution will cause variation of amount of solution. If mass and volume change, and he volume is not kept constant, then what affects theconcentration would be unknown. The concentrations are .025moldm-3, .05 moldm-3, .10 moldm-3, .15moldm-3, .20moldm-3, and .30moldm-3. The volume of the solution kept constant at 100cm3.

Materialsused in procedure:
* scale
* scoop
* magnet
* 100mL graduated flasks
* Flask lids
* 50mL beaker
* Screwdriver
* Tape water
* Thermodine stirring apparatus/thermodinestirrer
* Thermometer probe
* Conductivity probe
* Masking tape
* Plastic weighing dish
* pipette
* Pencil
* (KNO3) (Potassium Nitrate)
Procedure:
1. Gather materials.2. Calculate the number of moles using formula n=cV.
- n is number of moles, c is concentration, and v is volume.
3. Divide by 1000 to convert centimeters to decimeters.
4. Solve for mass usingn=m/M.
- n is number of moles, m is mass in grams, M is molar mass. M is found by adding mass of each element.
5. Record mass. Repeat steps 2-4 for following concentrations.
6. Zero Scale.
7.Scoop potassium nitrate out of jar and into weighing dish while using scoop.
8. Add or subtract the amount of the solute until you reach the mass calculated for your 0.025moldm-3
9. Put water inflask. Make sure bottom of meniscus is even with 100 mL line. Stoop down and check by looking at eye level at the 100 mL line.
10. Add potassium nitrate to tap water.
11. Log into computer.
12....