How do you convert water to steam?

Answer 1

You need to apply enough energy to the water to make it change phase to turn form a liquid to a gas. This is commonly achieved by applying thermal energy(heat) to liquid water, eg boiling a pot of water.

This is where a property called specific heat capacity comes into use. This is the amount of thermal(heat) energy that is needed to raise a specific amount of a substance by a certain amount interval of temperature. This is commonly given as the number of joules of energy to raise a gram or mole of the substance by a degree kelvin or Celsius.

for water it is 4.1813 J/(g·K)

this is the value for heating water under a constant pressure, which is most common(again think of boiling your pot of water), atmospheric pressure will not vary too much usually.

It is important that this value is dependent on the amount of the sample that is being heated, hence the name specific heat capacity. So the above value is to raise the heat of a gram of water by one degree kelvin, but if you had a kilo of water(1000g) then the value would be 1000 times greater i.e. 4181.3 J/(Kg.K)

Then all you do is apply enough energy to get water to 100 degrees Celsius, at this temperature water begins to boil i.e. turn into a gas, here is where the phase change comes into effect. This is called vaporization (turning the liquid into a gas) and each compound has a different phase diagram. This phase diagram shows different temperatures and pressures and a number of lines on it, by reading it correctly you can determine under what temperatures and pressures will water be a solid, liquid or a gas(or even when water can be in all 3 phases solid, liquid and gas).