Food Dye Concentration Lab

Pages #1087-1112 Problems #28-32, 65,67,68:

Pages #1087-1112 Problems #28-32, 65,67,68:

Interpreting Solubility Curves

Pages #1062-1072 Problems #1-2,10-15:

Concentrations of Solutions

Calorimetry Worksheet Practice

Energy and Specific Heat:

Page #1176 Problems #38,40:

Pages #1154-1158 Problems #22-25:

Enthalpy H Phase Change WS

Heat of Combustion of a Candle Lab

Purpose: 

To observe a burning candle and calculate the heat associated with the combustion reaction. 

Procedure: 

1) Measure and record the length of a candle in centimeters. 

2) Place the candle on a small piece of aluminum foil and measure the mass of the foil-candle system. 

3) Note the time as you light the candle. Let the candle burn for about five minutes. 

4) Extinguish the candle and record the time. 

5) Measure the mass of the foil-candle system again.

Data: 

Analyze and Conclude: 

1) 

2) The wick is the one that is burning. 

3) The wax is there to hold the wick in place. 

4) The air on top of the candle is hotter because heat rises. 

5) The candle lost 1.2 centimeters and lost .3 grams. For length it would be mostly the wax and for mass it would be the wick. 

6) The wick acts as towel and soaks up the wax. Then the wax and wick burn. 

7) C20 H42 30 1/2 O2 ---> 20CO2 + 21H2O 

8) 1.16g (1mol/282g) = .00411348 mol 

Pages #1189-1192 Problems #66-93:

Heat of Fusion Lab

Purpose: 

Determine the heat of fusion. 

Procedure: 

1) Start with 100 ml H2O at 50° C

2) Place into calorimeter (cup). Record temperature. 

3) Drop 2 to 3 ice cubes in. Stir don't run out of ice. 

4) Once temperature stabilizes around 0° C. Remove ice. 

5) Measure new volume. 

Data Table: 

Calculations: 

1) Mass of 100 ml H2O = 100g

2) Cal q= M x ^T x C  

q= 80g x 50° C x 4.18 KJ/mol

3) Determine q= 16,720 KJ

4) Mass of ice melted = 80g H2O

5) Mole of ice melted= 4.4 mole H2O

6) ^H fusion for ice = KJ/mol

    16,720/1000= 16.72 KJ/4.4 mole= 3.8 KJ/mol

Conclusion: 

^H= 6.01 KJ/mol 

^H= 3.8 KJ/mol 

Percent error: 36.7 percent off of the theoretical yield 

We had a lot of errors in our experiment the causes a large percent error. Some errors included waiting too long to put the ice cubes in so it was not at 100° C when we started. That means we did not need as much ice cubes. This caused a difference from the theoretical yield.