How many grams of cold water necessary to lower temperature in container

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Homework Help Overview

The problem involves determining the mass of cold water needed to lower the temperature of a warmer water sample. The context is thermal energy transfer between two bodies of water at different temperatures.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the energy equation related to heat transfer and the relationship between the heat lost by the warmer water and the heat gained by the cooler water. Questions arise regarding the definitions and implications of the terms used in the energy equation.

Discussion Status

Some participants have provided guidance on the relevant equation for energy transfer and the concept of heat exchange. There is an ongoing exploration of the reasoning behind the signs in the energy equation, indicating a productive dialogue without a clear consensus yet.

Contextual Notes

The original poster mentions being overwhelmed with multiple subjects, which may affect their ability to recall specific equations related to the problem.

Paulo Serrano
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Homework Statement


How many grams of 20 degree C water do I need to add to 100 grams of 80 degree C of water to get the final temperature down to 50 degrees C?


Homework Equations


I'm sure it's a pretty simple equation, but I don't know it. (I'm studying a lot of different things at once and am not in school)


The Attempt at a Solution


Not sure.

Thanks :)
 
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First you need to know the equation for energy, which is q=c*m*deltaT, where deltaT is T(final)-T(initial). You also know that q of the 20 degree water equals the negative of the 80 degree water. Given this, you should be able to solve for grams of 20 degree water.
 
q is heat energy, correct? Why is one the negative of the other?
 
One is negative of the other because the heat that leaves the 80 degree water is added to the 20 degree water.
 

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