Question:Q1,The following information may or may not be useful. For water:
cw = 4186 J·kg-1·K-1
Lvap = 2.26×106 J·kg-1
Lfus = 3.33×105 J·kg-1
279 mL of homemade lemonade in a styrofoam cup has a temperature of T = 15.7°C. Assume that the lemonade has the same thermal properties as water and the styrofoam cup is a good insulator.
What mass of ice (at 0°C) needs to be added to reduce the temperature of the lemonade to 0°C?
If 10.3 g of ice is added to the lemonade, what is the final temperature of the lemonade?
Instead of being cooled by the addition of ice the lemonade is instead heated on the stove to a final temperature of Tf = 86.2°C. At 40.0°C the volume of the lemonade is measured and found to have increased by 1.00 mL.
If the expansion is linear with temperature what is the increase in volume from Ti = 15.7°C to Tf = 86.2°C?
Q2, A hot reservoir at temperature Thot = 76.0°C is connected to a cold reservoir with a temperature of Tcold = 28.7°C by a metal rod.
The metal has a thermal conductivity of k = 156.7 W/m°C, a cross-section of A=46.8 cm2, and a length of L = 47.5cm.
What is the rate of heat flow along the rod?
How long does it take for 467.5 kJ to pass through the rod?
Which of the following changes would decrease the time needed for this amount of energy to pass through the rod?
Select all of the correct answers.
Select one or more:
Use a metal with a higher thermal conductivity.
Increase the cross-sectional area of the rod.
Increase the length of the rod.
Q3, A water bottle has 28.5 mL of air at the top. The bottle is removed from the fridge at 4.00°C, the lid is unscrewed and then replaced while being exposed to 1.00 atm of pressure. Assume air can be modeled as an ideal gas.
How many mols of air are in the top of the bottle?
The bottle is placed in a car and heats up to 46.1°C. What is the pressure of the air at the top of the bottle now? Assume that the water and bottle do not expand.
If the temperature remained at 4.00°C, what pressure would need to be applied on the gas to halve its volume?