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TUTORIAL FOR 1ST LAW OF THERMODYNAMICS ERT 108 PHYSICAL CHEMISTRY

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Presentation on theme: "TUTORIAL FOR 1ST LAW OF THERMODYNAMICS ERT 108 PHYSICAL CHEMISTRY"— Presentation transcript:

1 TUTORIAL FOR 1ST LAW OF THERMODYNAMICS ERT 108 PHYSICAL CHEMISTRY
ROHAZITA BINTI BAHARI

2 QUESTIONS ENTERNAL ENERGY, HEAT AND WORK
1) Jimmy wants the biggest balloon for his friend, Ali’s birthday. He bought a balloon from the convenience store, but its volume was only 4.00L. Therefore, he added Joule of heat and the balloon expended to 8.00L. What is the change in internal energy for this process?. Assume the pressure is 1.00 atm.

3 2) The firing od a potato cannon provides a good example of the heat and work associated with a chemical reaction. In a potato cannon, a potato is stuffed into a long cylinder that is capped on one end and open at the other. Some kind of fuel is introduced under the potato at the capped end-usually through a small hole-end ignited. The potato then shoots out of the cannon, sometimes flying hundreds of feet, and heat is given off to the surroundings. If the burning of the fuel performs 855J of work on the potato and produces 1422J of heat, what is internal energy for the burning of the fuel?.

4 PRESSURE-VOLUME WORK 3) Inflating a balloon requires the inflator to do pressure-volume work on the surroundings. If a balloon is inflated from a volume of 0.100L to 1.85L against an external pressure of 1.00 atm. How much work is done? (in Joule)

5 4) A balloon is being inflated to its full extend by heating the air inside it. In the final stages of this process, the volume of the balloon changes from 4.00X106 L to 4.50x106L by the addition of 1.3x108J of energy as heat. Assuming that the balloon expands against a constant pressure of 1.0 atm, calculate internal energy for the process. (to convert L.atm and J, use 1L.atm=101.3J)

6 THERMOCHEMICAL EQUITION
5) How much heat is released by burning 27.5g of CH4?. 6) How much heat is created by 79.2g O2?. 7) How many grams of N2 are needed to make kJ? 8) How many grams of H2 do you need to get - 155kJ?

7 THERMAL ENERGY-HEAT CAPACITY
9) A cheez-it has a mass of 50g and a specific heat of J/g°C. Find out how much thermal energy it would take to warm it from 22.1°C to 43.7°C?

8 10) The air in a room has a mass of 70kg and a specific heat of 1,000 J/kg°C. What is the change in thermal energy of the air when is cools from 50°C to 40°C?. 11) The temperature of a 5.0kg brick increases by 2°C when a 3,000J of the thermal energy are added to the brick. What is the specific heat of the brick?.

9 12)What is the total thermal energy change of a 3
12)What is the total thermal energy change of a 3.5kg chunk of graphite that changes from 20°C to 100°C?. The specific heat of carbon is 710J/kg°C. 13)There is a total thermal energy change of 53250J when a 1.5kg chunk of graphite heats from 20°C to 70°C. What is the specific heat of the graphite.

10 14) You mix 100mL of 70°C water with 150mL of a different water source
14) You mix 100mL of 70°C water with 150mL of a different water source. The mixture then reaches a temperature of 75°C. What was the temperature of the second water source?. 15) You have 2 samples of water. One samples is at a temperature of 15 degrees and another sample is at a temperature of 35 degrees. You take 350mL of the cooler water and mix it with hot water. How much hot water would u add to bring the temperature of 34 degree?.


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