Question

A 6.00 gram sample of water begins to melt at its melting point, then is heated up to its boiling point and boiled completely into steam. How many different equations must you use? How much total energy does this take?

a) 3 equations, 10 kJ
b) 2 equations, 6 kJ
c) 4 equations, 50 kJ
d) 1 equation, 20 kJ

Answer 1

You would need to use three equations to account for each phase change, and the total energy required is 14.9 kJ.

Step-by-step explanation:

In this scenario, a 6.00 gram sample of water undergoes three phase changes: melting, heating up to boiling point, and boiling into steam. Each phase change requires a certain amount of energy, and each can be represented by an equation. Therefore, you would need to use three equations to account for each phase change.

As for the total energy required, the energy to melt a gram of ice is 334 J and the energy to vaporize a gram of water at its boiling point is 2256 J. So, the total energy required can be calculated as:

(6 g)(334 J/g) + (6 g)(2256 J/g) = 14,904 J = 14.9 kJ