Learn the toughest concepts covered in your GOB - General, Organic, and Biological Chemistry class with step-by-step video tutorials and practice problems.

Matter and Measurements

**Temperature** is a measurement of how hot or cold a substance is based on its kinetic energy.

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Temperature (Simplified) Concept 1

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Now, before we can talk about temperature, we first need to talk about the overall idea of energy, energy is the capacity to do work or to produce heat. Now, heat is sometimes confused with temperature. They are not the same thing, what they are are different subsets of what we call thermal energy. Now, thermal energy is one of the subsets of energy itself. It's the some of the kinetic and potential energies of all atoms in an object. Remember kinetic energy is the energy of motion, potential energy is the energy of position. So we have energy which can be broken down into thermal energy. Thermal energy can be further broken down into temperature and heat temperature is just the average kinetic energy of an object. That is a measurement Of thermal energy. So when I say, the temperature is 100°C, which pretty hot. Uh that is what we refer to as temperature. It is a measurement of thermal energy. Heat though is not the same thing. Heat is just the flow of thermal energy from an object at a higher temperature to an object at a lower temperature. Remember, heat always moves from hotter. Took holder. So just remember when we're talking about temperature and heat, they're not the same thing. Temperature is a measurement of thermal energy. Heat is the flow of thermal energy.

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Temperature (Simplified) Example 1

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here, it says, from the image of provided below, determine which part of the cubes represent temperature and which part represents heat. All right, so let's do the easy part. First. Remember, heat represents the flow of transfer off thermal energy from, ah hotter object toe, a colder object. So that would mean that these wavy lines here would have to represent our heat temperature. Itself is a bit different temperatures, the result of the movement of molecules within a structure. So we'd say here that these little orange reddish balls they're spinning around, they're generating our temperature for the cubes. So we'd say inside the cube itself, there's temperature being generated. And since these molecules are moving more vigorously, that would mean that this has a higher temperature. Here they're more stationary because it's at a lower temperature. This justify why he is moving from the cube on the left towards the cube on the right, in Cuba on the right will just be at a lower temperature, and that's what we can say in terms of temperature and heat. When given these two cubes

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Problem

Which of the following containers would have the greatest flow of thermal energy in the form of heat?

A

B

C

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Temperature (Simplified) Concept 2

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Yeah. Now temperature can be measured in units off Celsius, Fahrenheit and Calvin. And when it comes to these temperature units, we can convert between them in order to convert between them. We just have to utilize certain formulas. Now, here we have purple boxes, and when we have these purple boxes, that means that that's a term or formula you have to memorize. Okay, you have to commit it to memory because oftentimes it's not given to you on an exam or quiz. Now the first one connects Calvin two degrees Celsius, and it's that Calvin equals degree Celsius plus to 73.15. Oftentimes, professors will drop the 0.15 part. But to be as accurate as possible, it's important that you use the whole number so to 73. from this equation, we can see that Kelvin directly connects two degrees Celsius and we could go between them. The next equation connects degrees Fahrenheit two degrees Celsius, and the equation is degrees Fahrenheit equals 1. times degree Celsius plus 32. So this formula here shows us that degrees Celsius is connected F. So from these three units, we can see that Celsius is in the middle, so Celsius acts as the bridge that connects Kelvin F. So just remember, when it comes to temperature, we have three units that we can use. And when it comes to changing between them, these are the two formulas you need to commit to memory Anytime you see a purple box, remember, that means you're gonna have to memorize either that term, that definition or, in this case, off formula.

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Temperature (Simplified) Example 2

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Let's take a look at the following example question here. It says one of the hottest recorded days in the country was 128 F in Lake Havasu City, Arizona. If the melting point of phosphorus is 44 15 degrees Celsius, what it exists as a solid or liquid on this extremely hot day? Alright, so we see that in the question. We're dealing with units of Fahrenheit and Celsius from the equations up above. We know what's the second one we're gonna have to use in some way. So we have degrees Fahrenheit equals 1.8 times degrees Celsius plus 32. They're giving me the temperature in Lake Havasu in Fahrenheit by me. I need to compare it to this melting point of phosphorus, which is in Celsius. If the temperature I find is equal to or greater than 44. degrees Celsius, that means that phosphorus will melt and it will be in its liquid. For if the temperature on this extremely hot day is not at least 44.15 degrees Celsius, then it won't be hot enough, and phosphorus will not melt and remain a solid so I'm gonna plug in what I have referred. Height, which is 1 28 and this is 1.8 degrees Celsius plus 32 subtract 32 from both sides. So when we do that, we get 96 equals 1.8 times degree Celsius. Divide both sides now by 1.8, and now we'll have the temperature in Lake Havasu in degrees Celsius, so our degrees Celsius here equals 53.3. Now we needed the temperature to would be at least 44.15 degrees Celsius for phosphorus to mount. This answer is much greater than it. So yes, it's hot enough for phosphorus to mount. Therefore, it will exist in its liquid form. Now that we've seen this example on how to relate Fahrenheit two degrees Celsius, move onto the next video and let's take a look at the practice question

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Problem

At what temperature is the temperature in degrees Fahrenheit equal to the temperature in degrees Celsius?

A

0º

B

25º

C

-40º

D

-29º

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