cwalker8184 Posted March 29, 2012 Report Share Posted March 29, 2012 I am need help really bad for Physical Science test tomorrow. The question is " 5600 J of heat are given off by a 600 g sample of iron. What was the temperature drop?" I'm not just looking for the answer, but how to arrive at the answer, so that I will know how to do it for the test. Quote Link to comment Share on other sites More sharing options...

CraigD Posted March 30, 2012 Report Share Posted March 30, 2012 Welcome to hypography, Curt! :) Hope we're not too late responding. I am need help really bad for Physical Science test tomorrow. The question is " 5600 J of heat are given off by a 600 g sample of iron. What was the temperature drop?" I'm not just looking for the answer, but how to arrive at the answer, so that I will know how to do it for the test.The concept you need for this question is called heat capacity, or specific heat. A good way to keep track of these ideas is to think of them as equations, and keep track of the units in which they measure. You question asks you to “solve for [imath]\Delta T[/imath]”: [math]5600 \,\text{J} \cdot \,\text{(something specific to iron)} \cdot 0.6 \,\text{kg} = \Delta T \,\text{K}[/math] So you need “something specific to iron” that has units [imath]\frac{\text{K}}{\text{J} \cdot \text{kg}}[/imath], or something in other units of temperature, energy, and mass. Such a unit is one of heat capacity. You may run into a wrinkle in this, because specific heat is sometime given in [imath] \frac{\text{J} \cdot \text{mole}}{\text{K}}[/imath] or similar, requiring you to convert from moles to units of mass. Sometimes, “mole”, which isn’t exactly a unit, isn’t written. However, most tables specific heat tables, including the one at the wikipedia link above, give a value in units of [imath]\frac{\text{energy} \cdot \text{mass}}{\text{temperature}} [/imath]. Quote Link to comment Share on other sites More sharing options...

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