Molecular Physics | Thermodynamics Answers

A bath contains 100kg of water at 60°C. Hot and cold taps are then turned on to deliver 20kg per minute each at temperatures 70°C and 10°C respectively. How long will it be before the temperature in the bath dropped to 45°C?

A sealed flask of capacity 500cm3 contains gas at a pressure of 1 atmosphere. If the temperature of the gas is raised from 10℃ to 35℃,without any change in volume, calculate the new pressure.

If two charged balloons are 20cm apart and they feel a force of electrical repulsion of 50N, what would the force of electrical repulsion become if the balloons were moved apart to a distance of 100cm?

A 20g cube of ice, initially at temperature of -5°C is put into some water in a Styrofoam cup. The initial temperature of the water is 50°C, and the ice cube absorbs 5kJ of heat before reaching thermal equilibrium with the water. Assume the ice absorbs heat only from the water. What final temperature does the mixture reach?

Which of the following is False

Group of answer choices

The higher the temperature at which a liquid boils, the larger the latent heat of vaporization of that liquid

Different liquids require different amounts of heat to go through phase change

The latent heat of fusion of water indicates the amount of heat needed to melt 1g or 1 kg of ice at 0°C.

During phase change the temperature of an object remains constant

1. A scientist very carefully does mechanical work on a container of liquid sodium. The liquid sodium loses 300 J of energy to its surroundings but gains 250 J of energy overall. How much work did the scientist do?

1. A scientist very carefully does mechanical work on a container of liquid sodium. The liquid sodium loses 300 J of energy to its surroundings but gains 250 J of energy overall. How much work did the scientist do?

Heat flows through a wooden board 30 mm thick at 0.0086 W/cm³ ,when one of its sides is 20˚C warmer than the other. Determine the thermal conductivity of the wood.

A small probe is made of stainless steel and has a length of 164.1 mm when being used to monitor the temperature in a furnace.
When the probe is removed for maintenance and allowed to cool to 20.0°C the length of the probe is measured as 162.2 mm.
What is the temperature of the furnace? (to 3 s.f and in °C)
[αsteel = 16.0×10−6 K−1]

A poorly ventilated commercial kitchen contains 120 kg of air at a temperature of 19°C and and with a relative humidity of 30% at the start of the evening shift.

At the end of the shift the temperature in the kitchen is 28°C and water is condensing on the walls and ceilings.

What is the minimum amount of water vapour that has been added to the air in the kitchen over the course of the shift? (to 2 s.f and in kg)