use a thermetor
There is a link between the mass of water heated and how much that water rises in temperature. It's called the "heat capacity" of water. It takes 1 joule of energy to raise the temperature of 1 gram of water by 1 degree celcius (or kelvin). So knowing this you can work out how much hotter a specific amount of water would become if you applied a known amount of energy to it.
The density of water changes at different temperatures. As temperature goes up, density goes down.
no
There's no reason for the mass of anything to depend on its temperature.
The number of calories required will depend on the mass of water which is to be heated.
Weigh mass before heating and weigh mass after heating. Before mass - after mass.
The mass of TiO2 does not increase as it is heated. As TiO2 is heated, the titanium becomes more oxidised, and increases in oxidation state, and so oxygen is added to the molecule, making TiO3. As oxygen is added to TiO2, the mass you measure increases, but it does not stay as TiO2.
Question makes no sense - unanswerable. Nothing changes mass when heated or cooled.
mass of water, initial temp of the water, final temp of water after the hot sinker is put into the water, the temp of the hot sinker (if it is heated in separate boiling water, the temperature of the water) and the specific heat of water ( 1 cal/g degree C)
Temperature of the water
Temprature affects the volume, since most objects expand when they are heated. And density is mass / volume.