Wednesday, June 11, 2014
Wednesday, May 7, 2014
Friday, May 2, 2014
Dye lab
CONCLUSION: The results, however wierd, sound farly reasonable when added together and compared to what the powder is, a drink mix. The percentages are reasonable. As far as mistakes go there were many posiblilitys. The largest being the possibility of cross contamination between solutions. Another is the miscalibration of the machine before testing. All things considered it was a good lab
Friday, April 25, 2014
Tuesday, April 22, 2014
Friday, April 18, 2014
Friday, April 11, 2014
Heat of Combustion of a Candle
Purpose:
To observe a burning candle and calculate the heat associated with the combustion reaction
Materials:
Ruler
Candle
Aluminum foil
Balance
Safety matches
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.
Note the time as you light the candle. Let the candle burn for about 5 minutes. Caution keep clothing away from flame. While you wait begin answering the data and conclusion questions.
3: Extinguish the candle and record the time.
4: Measure the mass of the foil candle system again. Do not try to measure the mass while the candle is burning.
Data
Length before: 5.9cm Mass before:1.53g
Length After: 3.5 cm Mass after: 1.16
Analysis and Conclusion
1: (description) the fuse is engulfed in flame as the flame spins gracefully off the top.
2: Wick
3: The wax holds it up and slows it down.
4: Because the flame puts off heat.
5: Loss .37g and 2.4 cm. This data the most consistent with the wax burning
6: You light the wick and it ignites and guides the flame from the burning wax.
7: C20H42 + 20 O2= 20 CO2 + 21 H2O
8: .37/283(molar mass)=.0013mol
9: 42 jk/mol
10: .05jk
Heat of Fusion of Ice-Lab
Purpose: The purpose of this experiment is to find the delta heat for water.
Procedure: 1) start with 100ml of water on a hot plate and make sure it is at 50 Celsius
2) Place into foam cup and record the temperature
3) Drop 2-3 ice cubes in and stir but don't run out of ice. If ice melts add more
4) Once temp stabilizes around 0 Celsius and remove ice
5) Measure new volume of the water
Data Table:
0 minutes 50 Celsius
1 minute 5 Celsius
2 minutes 3 Celsius
3 minutes 3 Celsius
4 minutes 0 Celsius
Starting Water: 100g
Ice water with cup: 165.46g
Cup: 7.49
Ice water: 157.97
Calculate:
1) mass of 100ml of water
100ml=100g
2) Calculate q = m x delta t x c
q= 100 g x 50 x 50 C= 250,000
3) Determine q ice
flip sign -250,00
4) Mass of ice melted
57.97 g
5) Moles of ice melted
57.97(1 mol/18)= 3.22
6) delta H fusion for ice kj
3.22 1 mol H2O
250,000jk x
7) delta H = 6.01 kj/mol
Conclusion:
If 100ml water is cooled to 0 Celsius with ice then the delta H will equal about 6.01 kj/mol because delta H for water is 6.01 kj/mol. This does support the hypothesis. This experiment went well except the cup had a small leak so it had to be plugged with fingers which could have contributed extra heat. Also it never was exactly 0 degrees. This experiment was successful because water was cooled to 0 Celsius the delta heat was found being about 6.01 kj/mol.
Thursday, April 10, 2014
Sunday, March 9, 2014
Pressure vs. temperature lab including questions and two graphs
1: Volume and # of moles.
2: There is a direct relationship between Pressure and Temp.
3: As pressure decreases -the amount of force exerted on it- the temperature decreases because the particles are under less pressure to move there for slowing down and when they slow down temperature decreases.
4: P/T=k
6: Pressure doubles as well.
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