User:Inconspicuum/Physics (A Level)/Temperature Questions

Heat and Energy

1. Carbon dioxide sublimes at 195°K. Roughly what energy per. particle does this correspond to?
2. A certain chemical reaction requires particles with mass of the order 10^-26kg to move, on average, at 10ms^-1. Roughly what temperature does this correspond to?
3. The boiling point of water is 100°C. Roughly what energy per. particle does this correspond to?
4. Thermionic emission from copper requires around 5eV of energy per. particle. How hot will the wire be at this energy level?

Specific Heat Capacity

1. How much work would it take to heat 100kg of liquid water from 20°C to 36.8°C?
2. How much work would it take to heat a well-insulated room from 15°C to 21°C, if the room is a cube with side length 10m, and the density of the air is 1.2kgm^-3?
3. A 10kg block of iron at 80°C is placed in the room above once it has reached 21°C. If the iron cools by 40°C, what is the new temperature of the room?

Ideal Gases

1. I heat some argon from 250K to 300K. If the pressure of the gas at 250K is 0.1 MPa, what is its pressure after heating?
2. The argon is in a 0.5m long cylindrical tank with radius 10cm. What volume does it occupy?
3. The argon is then squeezed with a piston so that in only occupies 0.4m of the tank's length. What is its new pressure?
4. What is its new temperature?
5. 25% of the argon is sucked out. What is its pressure now?

Kinetic Theory

1. Five molecules are moving at speeds of 1,5,6,8, and 36ms^-1. What is their mean square speed?
2. What is the mass of one molecule of N₂ (atomic mass 14, 1u = 1.66 x 10^-27kg)?
3. Atmospheric pressure is 101,325 Pa. If one mole of Nitrogen takes up 2.3 m³ at about 10°C, what is the mean square speed of the molecules in the air outside, assuming that the atmosphere is 100% nitrogen (in reality, it is only 78%)?
4. What is the average speed of a nitrogen molecule under the above conditions?
5. The particles in question 1 are duplicated 3000 times. If they have a completely unrealistic mass of 1g, what is their pressure when they are crammed into a cube with side length 0.5m?

Boltzmann Factor

1u = 1.66 x 10^-27 kg

g = 9.81 ms^-2

1. A nitrogen molecule has a molecular mass of 28u. If the Earth's atmosphere is 100% nitrous, with a temperature of 18°C, what proportion of nitrogen molecules reach a height of 2km?
2. What proportion of the molecules in a box of hydrogen (molecular mass 2u) at 0°C have a velocity greater than 5ms^-1?
3. What is the temperature of the hydrogen if half of the hydrogen is moving at at least 10ms^-1?
4. Some ionised hydrogen (charge -1.6 x 10^-19 C)is placed in a uniform electric field. The potential difference between the two plates is 20V, and they are 1m apart. What proportion of the molecules are at least 0.5m from the positive plate (ignoring gravity) at 350°K?