A glass of ice at 0 degrees celsius changes to a glass of water at 0 degrees celsius. What caused the ice to change to water ?
1 answer:
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Answer: 20.7 kJ
Explanation:
According to first law of thermodynamics:
=Change in internal energy
q = heat absorbed or released
w = work done or by the system
w = work done on the system= {Work is done on the system is positive as the final volume is lesser than initial volume}
w = 4.51 kcal = (1kcal = 4.184kJ)
q = +1.79 kJ {Heat absorbed by the system is positive}
Thus for a system that receives 1.79 kJ of heat from surroundings and has 4.51 kcal of work done on it at the same time is 20.7 kJ
The balanced chemical reaction is :
Number of moles of Na, .
Now, from balance chemical reaction we can see that 1 mole of oxygen reacts with 4 moles of sodium.
So, number of moles of oxygen are :
So, amount of oxygen required is :
Therefore, 5.08 gram of oxygen will react with 14.6 gram of sodium.