# How much heat in joules is needed to raise the temperature

• comoore
In summary, the question asks for the amount of heat in joules needed to raise the temperature of 7.0 L of water from 0°C to 78.0°C. The equation used is 7000g x 78°C = 546000 calories, which is then converted to 2.28x10^6 J. The same equation can be used for 7.5 L of water to get a result of 2.73x10^6 J.
comoore

## Homework Statement

How much heat in joules is needed to raise the temperature of 7.0 L of water from 0°C to 78.0°C? (Hint: Recall the original definition of the liter.)

## Homework Equations

How much heat in joules is needed to raise the temperature of 7.5 L of water from 0°C to 87.0°C? (Hint: Recall the original definition of the liter.)
2.73e+06 J

## The Attempt at a Solution

I think so...

I did 7000 gm x 78 C=546000 calories
546000x4.184j/calorie=2284.5 kj
Then converted kj to j

OH. MY. GOSH. I didn't put the 10 in when I answered. The answer is correct. 2.28x10^6 J.

Greg Bernhardt
comoore said:
7.0 L of water
comoore said:
7.5 L of water
Better turn off the tap.

Chestermiller and Bystander

## 1. How is heat measured in joules?

Heat is measured in joules (J) using a scientific instrument called a calorimeter. This device measures the amount of heat absorbed or released by a substance during a chemical or physical change.

## 2. What factors affect the amount of heat needed to raise the temperature?

The amount of heat needed to raise the temperature of a substance depends on its mass, specific heat capacity, and the change in temperature. The higher the mass and specific heat capacity, and the larger the change in temperature, the more heat will be required.

## 3. How is the specific heat capacity of a substance determined?

The specific heat capacity of a substance is determined by conducting experiments to measure the amount of heat needed to raise the temperature of a known mass of the substance by a certain amount. This value is then used in calculations to determine the amount of heat needed for other temperature changes.

## 4. Can the amount of heat needed to raise the temperature vary for different substances?

Yes, the specific heat capacity of substances varies and can affect the amount of heat needed to raise the temperature. For example, water has a higher specific heat capacity compared to metals, meaning it takes more heat to raise the temperature of water compared to the same mass of metal.

## 5. How does the unit of temperature affect the calculation of heat in joules?

The unit of temperature used in the calculation of heat in joules can affect the final result. For example, using degrees Celsius or Fahrenheit will result in a different value compared to using Kelvin. It is important to use the appropriate unit of temperature when calculating heat in joules.

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