200 mL of 100°C hot tea was poured in a 250 mL vacuum flask and sealed. 0.01 mL of water in the tea was then evaporated in the flask after an hour. Assume no energy is lost to the surroundings and the temperature is kept at 100°C after an hour. Given density of water at 100°C = 0.958 g/mL; specific latent heat of vaporization of water = 2260 J/g; R = 0.0821 L-atm/mol-K; molar mass of water = 18.02 mol/g; 0°C = 273.15 K. (a) What is the mass (in mg) of 0.01 mL water at 100°C? (b) How much energy (in J) is required to vaporize 0.01mL of water? (c) How many moles (in mmol, i.e. 10-³ mol) of gases inside the vacuum flask in the beginning? (d) What is the pressure (in atm) inside the flask after an hour? (Hint: Consider the number of mole of water vapor vaporized from 0.01 mL water.)

200 mL of 100°C hot tea was poured in a 250 mL vacuum flask and sealed. 0.01 mL of water in the tea was then evaporated in the flask after an hour. Assume no energy is lost to the surroundings and the temperature is kept at 100°C after an hour. Given density of water at 100°C = 0.958 g/mL; specific latent heat of vaporization of water = 2260 J/g; R = 0.0821 L-atm/mol-K; molar mass of water = 18.02 mol/g; 0°C = 273.15 K. (a) What is the mass (in mg) of 0.01 mL water at 100°C? (b) How much energy (in J) is required to vaporize 0.01mL of water? (c) How many moles (in mmol, i.e. 10-³ mol) of gases inside the vacuum flask in the beginning? (d) What is the pressure (in atm) inside the flask after an hour? (Hint: Consider the number of mole of water vapor vaporized from 0.01 mL water.)

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter11: Energy In Thermal Processes

Section: Chapter Questions

Problem 35P

See similar textbooks

Similar questions

A steam pipe is covered with 1.50-cm-thick insulating material of thermal conductivity 0.200 cal/cm C s. How much energy is lost every second when the steam is at 200.C and the surrounding air is at 20.0C? The pipe has a circumference of 800. cm and a length of 50.0 m. Neglect losses through the ends of the pipe.
An aluminum calorimeter with a mass of 100 g contains 250 g of water. The calorimeter and water are in thermal equilibrium at 10.0C. Two metallic blocks are placed into the water. One is a 50.0-g piece of copper at 80.0C. The other has a mass of 70.0 g and is originally at a temperature of 100C. The entire system stabilizes at a final temperature of 20.0C. (a) Determine the specific heat of the unknown sample. (b) Using the data in Table 19.1, can you make a positive identification of the unknown material? Can you identify a possible material? (c) Explain your answers for part (b).
A hollow aluminum cylinder 20.0 cm deep has an internal capacity of 2.000 L at 20.0C. It is completely filled with turpentine at 20.0C. The turpentine and the aluminum cylinder are then slowly warmed together to 80.0C. (a) How much turpentine overflows? (b) What is the volume of the turpentine remaining in the cylinder at 80.0C? (c) If the combination with this amount of turpentine is then cooled back to 20.0C, how far below the cylinders rim does the turpentines surface recede?
An aluminum rod and an iron rod are joined end to end in good thermal contact. The two rods have equal lengths and radii. The free end of the aluminum rod is maintained at a temperature of 100.C, and the free end of the iron rod is maintained at 0C. (a) Determine the temperature of the interface between the two rods. (b) If each rod is 15 cm long and each has a cross-sectional area of 5.0 cm2, what quantity of energy is conducted across the combination in 30. min?
The latent heat of vaporization for water at room temperature is 2 430 J/g. Consider one particular molecule at the surface of a glass of liquid water, moving upward with sufficiently high speed that it will be the next molecule to join the vapor. (a) Find its translational kinetic energy. (b) Find its speed. Now consider a thin gas made only of molecules like that one. (c) What is its temperature? (d) Why are you not burned by water evaporating from a vessel at room temperature?
Stars A and B have the same temperature, but star A has twice the radius of star B. (a) What is the ratio of star As power output to star Bs output due to electromagnetic radiation? The emissivity of both stars can be assumed to be 1. (b) Repeat the question if the stars have the same radius, but star A has twice the absolute temperature of star B. (c) Whats the ratio if star A has both twice the radius and twice the absolute temperature of star B?
A firewalker runs across a bed of hot coals without sustaining burns. Calculate the heat transferred by conduction into the sole of one foot of a firewalker given that the bottom of the foot is a 3.00-mm-thick callus with a conductivity at the low end of the range for wood and its density is 300 kg/m3. The area of contact is 25.0 cm2 the temperature of the coals is 700 , and the time in contact is 1.00 s. Ignore the evaporative cooling of sweat.
An aluminum rod and an iron rod are joined end to end in good thermal contact. The two rods have equal lengths and radii. The free end of the aluminum rod is maintained at a temperature of 100.C, and the free end of the iron rod is maintained at 0C. (a) Determine the temperature of the interface between the two rods. (b) If each rod is 15 cm long and each has a cross-sectional area of 5.0 cm2, what quantity of energy is conducted across the combination in 30. min?
A 3.00-g copper coin at 25.0C drops 50.0 m to the ground. (a) Assuming 60.0% of the change in gravitational potential energy of the coin-Earth system goes into increasing the internal energy of the coin, determine the coins final temperature. (b) Does the result depend on the mass of the coin? Explain.
A glass coffee pot has a circular bottom with a 9.00-cm diameter in contact with a heating element that keeps the coffee warm with a continuous heat transfer rate of 50.0 W (a) What is the temperature of the bottom of the pot, if it is 3.00 mm thick and the inside temperature is 60.0C ? (b) If the temperature of the coffee remains constant and all of the heat transfer is removed by evaporation, how many grams per minute evaporate? Take the heat of vaporization to be 2340kJ/kg.
A cylinder of volume 50.0 cm3 made of Pyrex glass is full to the brim with acetone. If the cylinder and acetone are warmed by 30.0C, (a) what is the change in volume of the glass? (b) Of the acetone? (c) Will any acetone spill out of the cylinder? (See Section 10.3.)
Assume you are measuring the specific heat of a sample of originally hot metal by using a calorimeter containing water. Because your calorimeter is not perfectly insulating, energy can transfer by heat between the contents of the calorimeter and the room. To obtain the most accurate result for the specific heat of the metal, you should use water with which initial temperature? (a) slightly lower than room temperature (b) the same as room temperature (c) slightly higher than room temperature (d) whatever you like because the initial temperature makes no difference