1. Typical temperatures in the interior of the Earth and Sun are about `4.0 times 10^3°C` and `15times10^6°C`, respectively. (a) What are these temperatures in kelvins? (b) What percent error is made in each case if a person forgets to change °C to K?

2. A storage tank at STP contains `18.5\ kg` of nitrogen(`N_2`). (a) What is the volume of the tank? (b) What is the pressure if an additional `15.0\ kg` of nitrogen is added without changing the temperature?

3. If `18.75\ mol` of helium gas is at `10.0°C` and a gauge pressure of `0.350\ atm`, (a) calculate the volume of the helium gas under these conditions. (b) Calculate the temperature if the gas is compressed to precisely half the volume at a gauge pressure of `1.00\ atm`.

4. A tank contains `26.0\ kg` of `O_2` gas at a gauge pressure of `8.70\ atm`. If the oxygen is replaced by helium, how many kilograms of the latter will be needed to produce a gauge pressure of `7.00\ atm`?

5. If `61.5\ L` of oxygen at `18.0°C` and an absolute pressure of `2.45\ atm` are compressed to `48.8\ L` and at the same time the temperature is raised to `50.0°C`, what will the new pressure be?

6. A helium-filled balloon escapes a child's hand jat sea level and `20.0°C`. When it reaches an altitude of `3000\ m`, where the temperature is `5.0°C` and the pressure is only `0.70\ atm`, how will its volume compare to that at sea level?

7. A cubic box of volume `5.1 times 10^(-2)\ m^3` is filled with air at atmospheric pressure at `20°C`. The box is closed and heated to `180°C`. What is the net force on each side of the box?