Question

You put 330 g of water at 23 ∘C into a 500-W microwave oven and accidentally set the time for 20 min instead of 2.0 min. Part A How much is left at the end of 20 min?

Answer 1

Answer:$47.07g$

Explanation:

500 watts is equivalent to 500J/s

20 minutes is equivalent to 20*60seconds which is 1200 s

330g is equivalent to 330/1000kg which is 0.33kg

The temperature will be (100-23) which is 77°C

The energy will be:

$Energy=500J/s * 1200s$

$Energy=600kJ$

Now we can apply:

 Q=$C_{p}$*m*ΔT

 Q=4.186kJ/kgC * 0.33kg * 77°C

 Q=106.37kJ

Energy to boil water is 2260J/kg

2260J/kg*0.33=

so The energy available will be:

 =745.8kJ-106.37kJ

 =639.43kJ

Now the remaining water will be:

=(1-639.43kJ/745.8kJ)*0.33

$=47.07g$