CREATING A “YUMMY” SOLUTION LAB

Boss:______Maid:______Secretary:______Gopher:______

Date______

Period______

Helpful hints: 1 mL of water = 1 gram of water

1L of water = 1 Kg of water

1 000 mL = 1 L

OBJECTIVE : To illustrate the concept of making and calculating the concentrations of solutions. To be able to express the concentration of solutions using several types of units.

BACKGROUND: You and your research and development team have been hired by Hutson & Jordan Beverages to come up with a new flavor for their line of fruit beverages. You must experiment to come up with a new flavor, using the raw materials that are available. In order for you to patent your beverage, you must be able to accurately determine, record and reproduce the solution concentrations you come up with.

MATERIALS: Dixie cups, plastic spoon, napkins, balance, wax paper for weighing, 400 mL food grade beaker

PROCEDURE:

  1. Fill a 400 mL food-grade beaker up to the 150 mL line with water from the containers provided. Remember that 1ml = 1g for water….so you DON’T have to weigh it!
  2. Place a piece of wax paper on a balance and weigh out the amount of solute(s) you think you want to start with to create your solution. Record this mass.
  3. Add your solute to the solvent in the beaker and stir with a spoon. DO NOT put the spoon directly on the table…yuck! – Also, do not put the spoon in your mouth!!
  4. Pour the solution from the beaker into a Dixie cup for a taste test.
  5. If you are happy with the result you can go on to step 6. If not, retry until you get a solution you are happy with.
  6. Come up with a name for your new creation, as well as the data for their solution in data Table 1.

Data Table 1

Team member / Solution name / Solvent (g) / Solute (g) / Final Solution mass (g)
  1. Among your team, you will need to determine which is the best solution, and use ONLY this solution for the calculations section. The solution you have chosen to use is :______
  1. Calculate the concentration of your solution using the equation below, and express it as:

a) % solution

b) pph

c) ppt

d) ppm

Remember: PERCENT SOLUTION = ( g solute / g solution) x 100

  1. Now that you have a good recipe for your beverage, you’ve been asked to make enough to serve a party of your friends. Calculate how much solute you would need to make 200 L of your beverage.
  1. Finally, here is a challenging last problem. At Hutson & Jordan’s beverage manufacturing plant, they require that all solution concentrations be expressed in Molarity. ( I think this goes back to their pre-beverage producing days - when they were Chemistry teachers). Molarity is just another type of unit used to express solution concentrations. The formula is:

Molarity (M) = moles of solute  L of solution

The mole is a counting unit (just like dozen, ream, gross etc.). 1 mole = 6.02 x 1223 particles. Since you can’t SEE the individual particles (molecules) of sugar (C6H12O6) there is a nice relationship between mass and number of moles. This is the Gram Formula Mass. It comes from adding up all of the atomic masses on the periodic table for each element in a molecule. This sum is the mass of 1 mole of (in this case) sugar molecules.

To calculate Molarity of your sugar solution:

  1. The Gram Formula Mass of C6H12O6 = 180 g/mole
  1. Divide the mass of sugar used by the Gram Formula Mass from above : ______g  _____g/mole
  1. The answer for #2 above IS the number of moles of sugar you used: ______moles
  1. Now using the equation for Molarity, plug in your number of moles, and divide by the number of Liters of Solution. BE CAREFUL – this is the total volume of solute PLUS solvent.
  1. Molarity = ______mole/L