calculate the amount of energy (kJ) lost when 50 mL of water at 0 Celcius freezes at 0 Celcius
To calculate the amount of energy lost when water freezes, we need to consider the energy required for the phase change from liquid to solid. This can be found using the equation:
Energy lost = mass of water × specific heat capacity × temperature change
First, we need to determine the mass of water in grams. We can do this by using the density of water, which is 1 g/mL. So 50 mL of water can be converted to 50 grams.
Next, we need to find the specific heat capacity of water, which is the amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius. The specific heat capacity of water is approximately 4.18 J/g°C.
Now, we can calculate the energy lost:
Energy lost = mass of water × specific heat capacity × temperature change
Since the water is freezing at 0°C, the temperature change is 0 - 0 = 0°C.
So the energy lost = 50 g × 4.18 J/g°C × 0°C = 0 J
To convert from J (joules) to kJ (kilojoules), divide the energy value by 1000.
Energy lost = 0 J ÷ 1000 = 0 kJ
Therefore, no energy is lost during the freezing of water at its freezing point.