The water at the top surface cools because evaporation is taking place. A convection current then makes the rest of the water cool. Explain how this convection current is produced.
Name the process through which thermal energy travels across the pan’s base.
Copper stays solid when heated to $1000\,^{\circ}\text{C}$. State one more reason why it is sensible to make a pan out of copper.
The water in the pan is heated from $17^{\circ}\text{C}$ until it begins to boil at $100^{\circ}\text{C}$. The specific heat capacity of water is $4200\,\text{J (kg }^{\circ}\text{C)}^{-1}$ and the pan contains 750 g of water. Calculate the energy needed to raise the temperature of the water from $17^{\circ}\text{C}$ to $100^{\circ}\text{C}$.
State two differences between boiling and evaporation.
At $100^{\circ}\text{C}$ the water’s temperature no longer rises, even though energy continues to be transferred to it. Explain, in terms of molecules, why thermal energy is needed to change water from a liquid into a gas.
The specific latent heat of vaporisation of water is $2.3 \times 10^6\,\text{J kg}^{-1}$. Thermal energy is supplied to the boiling water at a rate of $1300\,\text{J s}^{-1}$. Calculate the mass of water that turns into vapour in the 10 minutes immediately after the water reaches $100^{\circ}\text{C}$.