An aluminum calorimeter with a mass of 100 g contains 250 g...

An aluminum calorimeter with a mass of 100 g contains 250 g of water. The calorimeter and water are in thermal equilibrium at $10.0^{\circ} \mathrm{C}$ . Two metallic blocks are placed into the water. One is a $50.0-\mathrm{g}$ piece of copper at $80.0^{\circ} \mathrm{C} .$ The other block has a mass of 70.0 $\mathrm{g}$ and is originally at a temperature of $100^{\circ} \mathrm{C}$ . The entire system stabilizes at a final temperature of $20.0^{\circ} \mathrm{C}$ (a) Determine the specific heat of the unknown sample. (b) Guess the material of the un- known, using the data in Table $20.1 .$

Key Concepts

Calorimetry

Calorimetry is the science of measuring the amount of heat exchanged during physical or chemical processes. It typically involves isolating a system, such as a calorimeter, to monitor temperature changes and deduce quantitative energy transfers, relying on the principle that energy is conserved in these processes.

Thermal Equilibrium

Thermal equilibrium is a state where all parts of a system reach a uniform temperature with no net heat flow between them. This concept is crucial in calorimetry, as it allows the assumption that the final temperature is the same throughout the system, simplifying energy balance calculations.

Specific Heat Capacity

Specific heat capacity is a property of a material that indicates the amount of heat required to change the temperature of one unit of mass by one degree Celsius. It is an essential parameter in calorimetry, allowing the calculation of heat absorbed or released during temperature changes.

Energy Conservation in Heat Transfer

The principle of energy conservation in heat transfer states that in an isolated system, the total heat lost by substances at higher temperatures equals the total heat gained by substances at lower temperatures. This principle is fundamental in solving calorimetry problems by enabling the setup of energy balance equations to find unknown thermal properties.

Transcript

00:01 In this video, i'm going to be looking at heat transfer between objects in a closed system.

00:06 All right.

00:07 So what i have is a calorimeter.

00:09 It's aluminum.

00:10 It's made of 100 grams of aluminum.

00:14 So its mass is 100 grams.

00:17 It's filled with a mass of 250 grams of water.

00:23 And it is at an initial temperature of 10 .0 degrees celsius.

00:29 And into this calerimeter, we're going to place two blocks.

00:33 One is a block of copper, and that weighs 50 .0 grams, and is at an initial temperature of tc of 80 .0 degrees c.

00:50 And we have a block of an unknown material, and we know that weighs 70 .0 grams, and it is at an initial temperature t unknown of 100 degrees celsius.

01:06 We're now going to wait for this system to come to an equilibrium temperature, and when it does, we find that our final temperature is 20 .0 degrees celsius.

01:19 And what i want to find is the specific heat of my unknown sample, so my mu block, and i want to guess with that material.

01:30 Is once i have its specific heat.

01:33 All right, so let's see.

01:35 I know that the heat gained by the calorimeter, so the aluminum plus water, must equal the heat lost by our two blocks...

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