# Thermodynamics question with heat gain from surroundings considered

• FaroukYasser
In summary: Your 1st method looks right. The wording is poor. There is heat gained from the surroundings plus heat gained from the heater.
FaroukYasser

## Homework Statement

A heater with a variable power is surrounded by ice in a funnel. The heater is turned on on 70W and the ice starts melting. once the rate of dropping of droplets is constant. The mass of water falling is then calculated for 5 minutes and it is found that 0.26 g/s falls every second. The experiment is repeated for 110W for 5 minutes also and the mass is found to be 0.38 g/s, Find:

1) The latent heat of fusion of ice in J/g
2) The heat gained from the surrounding per second

## Homework Equations

Energy supplied by heater + heat gained from surrounding = mass * latent heat of fusion or in symbols:
E + h = mL

## The Attempt at a Solution

Okay so I am having two ideas to solve this and I am not sure which one I should choose:
Method 1:
For the first time with 70 W.
E + h = mL
(70x1) + h = 0.26L (Equation 1)

For the second time with 110 W
(110x1) + h = 0.38L (Equation 2)

Equation 2 - Equation 1
40 = 0.12L >>>> L = 333 J/g to 3s.f

subbing in L into any equation. h = 16.7 J/s (W)

Method 2
L = E/m
using the first value once. L = 70/0.26 = 269.2
using second valiue of L = 110/0.38 = 289.5
Average is 279 J/gWhich method should I use?. does method one have any flaws and if so what are they. does Method 2 have any flaws and if so what is it?

Your 1st method looks right. The wording is poor. There is heat gained from the surroundings plus heat gained from the heater.

rude man said:
Your 1st method looks right. The wording is poor. There is heat gained from the surroundings plus heat gained from the heater.
Hi
Thanks for your reply :). I was wandering what you meant by "wording is poor" and if there is anything i can improve. Also in method 1, are we neglecting the heat energy that is lost from the heater to the surrounding or does the constant rate of dripping indicate that all the heat from the heater is supplied to the ice?

## 1. How does heat gain from surroundings affect thermodynamics?

Heat gain from surroundings can affect thermodynamics in several ways. It can increase the internal energy of a system, leading to a higher temperature. This can also cause changes in the system's entropy, as heat transfer from the surroundings can lead to an increase or decrease in disorder within the system.

## 2. What is the relationship between heat gain and work in thermodynamics?

In thermodynamics, the relationship between heat gain and work is described by the first law of thermodynamics, which states that the change in internal energy of a system is equal to the heat added to the system minus the work done by the system. This means that heat gain from surroundings can result in an increase in the work done by the system, or vice versa.

## 3. How does heat gain affect the second law of thermodynamics?

The second law of thermodynamics states that the total entropy of a closed system will always increase over time. Heat gain from surroundings can affect this law by either increasing or decreasing the system's entropy. If the heat gain leads to an increase in temperature and disorder within the system, the entropy will also increase. However, if the heat gain leads to work being done by the system and a decrease in disorder, the entropy may decrease instead.

## 4. Can heat gain from surroundings be reversed in thermodynamics?

In theory, heat gain from surroundings can be reversed in thermodynamics. This is because the first law of thermodynamics states that energy cannot be created or destroyed, only transferred or converted from one form to another. Therefore, if a system has gained heat from the surroundings, it is possible for that heat to be removed and returned to the surroundings.

## 5. How does heat gain from surroundings affect the efficiency of a thermodynamic process?

The efficiency of a thermodynamic process is affected by heat gain from surroundings in two ways. First, if the heat gain increases the temperature of the system, it can lead to a more efficient conversion of heat into work. Second, if the heat gain results in an increase in the system's entropy, it can decrease the efficiency of the process as more energy is lost to disorder. Ultimately, the effect of heat gain on efficiency depends on the specific thermodynamic process and conditions involved.

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