# What Calculations Are Needed to Convert Steam to Water and Ice to Steam?

• xxiangel
In summary, the teacher says that the amount of heat needed to change 400 grams of steam from 200 degrees to 100 degrees is -985,000 Joules. The amount of heat needed to change 1 kg of ice from -20 degrees Celsius to 130 degrees Celsius is 3,100,000 Joules. And to work out these problems, the student should ask a teacher.
xxiangel

How much heat must be taken away from 400 grams of steam at 200 degrees to change it into water at 100 degrees? (Teacher says answer is -985,000 J)

How much heat must be absorbed by 1 kg of ice at -20 degrees Celcius to change it to steam at 130 degrees? (Answer is 3,100,000 J)

If someone could please show me how to work out these problems, it would be wonderful! Thank you so much!

xxiangel said:
How much heat must be taken away from 400 grams of steam at 200 degrees to change it into water at 100 degrees? (Teacher says answer is -985,000 J)
How many moles of H2O in 400 g. of steam? What heat is given off in cooling to 100 deg. C? What is the heat removed from water turning from vapour to liquid?

How much heat must be absorbed by 1 kg of ice at -20 degrees Celcius to change it to steam at 130 degrees? (Answer is 3,100,000 J)
Use the same approach as above.

AM

its very very easy...

what andrew said is right...but i will explain it to u...
when steam is to be converted into water it has to lose heat...but one important thing u have to notice is that...when a substance is changing its phase its losing more heat than when a small temperature change occurs...
first let's take steam from 200 to equilibrium..ie 100 degrees...for that heat required is equal to...Q=.4*c*(373-473)...now,steam has to spend some energy to convert steam into water...for that Q1=L*.4...where L is the latent heat of vapourization...then add Q & Q1...remember the added value will be negative as the heat energy is lost here and not gained...remember to convert grams into kilograms for getting answer in SI units...do the same for the second question as well...here Q maybe positive as here we need more energy to convert a solid to vapour...

finally just remember this...we need a lot of energy to change the phase of a substance...and always calculate Q by dividing it into various Qs wherever a phase change is taking place...ok yaaaaaar

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## What is temperature?

Temperature is a measure of the average kinetic energy of the particles in a substance. It is commonly measured in degrees Celsius (°C) or degrees Fahrenheit (°F).

## Why is temperature important?

Temperature is important because it affects many physical and chemical properties of substances, such as their state (solid, liquid, gas), density, and solubility. It also plays a crucial role in biological processes and can impact the health and well-being of living organisms.

## What are the common temperature problems?

Some common temperature problems include inaccurate temperature readings, inconsistent temperature measurements, and difficulty maintaining a desired temperature. Other problems may include extreme temperatures, such as heat waves or cold spells, which can impact human health and the environment.

## How can temperature problems be solved?

The solution to temperature problems depends on the specific issue. In cases of inaccurate temperature readings, calibrating or replacing measuring instruments may be necessary. For inconsistent temperature measurements, identifying and addressing the source of the inconsistency is key. Maintaining a desired temperature may require adjusting heating or cooling systems. Extreme temperatures may be mitigated through preparedness and adaptation measures.

## What are some factors that can affect temperature measurements?

Some factors that can affect temperature measurements include humidity, air pressure, altitude, and proximity to heat sources. Additionally, human error, equipment malfunction, and external interferences can also impact temperature readings.

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