# Mass of water given only power and density

• cheekyhouidini
In summary, the conversation discusses a thermodynamics question regarding the speed of vapour leaving a kettle. The first question asks for the amount of energy absorbed by the water in one second, while the second question asks for the amount of water boiled in one second. The relevant equations are provided and the conversation touches on the specific heat capacity of water and the temperature of the water.
cheekyhouidini
Homework Statement
This is apart of a larger thermodynamics question surrounding the speed of vapour leaving a kettle but I am stuck on this part. The question is as below:
Water boils in a kettle. The power absorbed by the water is 1 kW and steam escapes
through a spout of cross-sectional area 2 cm2
. Assuming the pressure of the vapour
in the kettle equals atmospheric pressure (101 kPa) and the steam can be treated
as an ideal gas
The first question is how much energy is absorbed by the water in one second? and the second which i am stuck on is: given the density of water (1000kg/m3), how much water is boiled in one second?

Any help would be greatly appreciated, cheers :)
Relevant Equations
Density= 1000kg/m3 , Power= 1kW
Cannot figure out where to start, apart from maybe something to do with specific heat capacity of water?

cheekyhouidini said:
Homework Statement:: This is apart of a larger thermodynamics question surrounding the speed of vapour leaving a kettle but I am stuck on this part. The question is as below:
Water boils in a kettle. The power absorbed by the water is 1 kW and steam escapes
through a spout of cross-sectional area 2 cm2
. Assuming the pressure of the vapour
in the kettle equals atmospheric pressure (101 kPa) and the steam can be treated
as an ideal gas
The first question is how much energy is absorbed by the water in one second? and the second which i am stuck on is: given the density of water (1000kg/m3), how much water is boiled in one second?

Any help would be greatly appreciated, cheers :)
Relevant Equations:: Density= 1000kg/m3 , Power= 1kW

Cannot figure out where to start, apart from maybe something to do with specific heat capacity of water?
Given that the vapour pressure is 1atm, what do you think the temperature of the water is? What is the 1kW achieving?

## 1. What is the formula for calculating the mass of water given only power and density?

The formula for calculating the mass of water is:

Mass = Power / (Density x Acceleration due to gravity)

## 2. How is the power of water related to its mass?

The power of water is directly proportional to its mass. This means that as the mass of water increases, its power also increases.

## 3. Can power and density be used to accurately determine the mass of water?

Yes, power and density can be used to accurately determine the mass of water. However, other factors such as temperature and pressure may also need to be taken into account for a more precise calculation.

## 4. How does the density of water affect its mass?

The density of water directly affects its mass. The higher the density of water, the more mass it will have per unit volume.

## 5. Is the mass of water constant or does it vary?

The mass of water can vary depending on the conditions it is in. For example, the mass of water will increase if it is at a lower temperature or under higher pressure.

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