Nature of Energy - Video Tutorials & Practice Problems

Nature of Energy

thermal chemistry is the study of matter and energy associated with chemical reactions or physical changes. Energy itself is just the capacity to do work or to produce heat. Now, when we talk about energy, realize that there are different types of energy. But in this chapter, we're only gonna focus on a selected few. Now, when we take a look at the big picture energy itself, we can say here that it can be broken down initially into either the position of atoms or the motion of atoms. When we're talking about the position of atoms, this is just simply our potential energy, our energy off position. And then if we're talking about the movement or motion of atoms, this is connected to kinetic energy. Now, both potential energy and kinetic energy can be further broken down into other types of energy potential energy. We can connect it to another one which deals with the chemical bonds of atoms. This is just simply chemical energy. And then kinetic energy can be broken down further into energy associate ID with temperature generated by motion of atoms. So this would be called thermal energy. So just remember, energy is just the capacity to work and to produce heat. And when we're talking about energy in this chapter, we're mainly concerned with these different types of energy forms. Now, of course, there are other types of energy that exist. We'll go into those in later chapters, but for now, just remember these particular for

Nature of Energy

in our discussion of the concept of energy, it's important to remember that the S I unit for energy is Jewell. And it's named after the English scientist James Jewell. When it comes to Jules, we're going to say that there are three particular types of conversion factors associated with it. We're going to stay here for the first one. We have one calorie, which is lower, Casey. This equals 4.184 jewels. Next, we have one capital C calorie. This one is associated with food nutrition. This particular calorie equals 4184 jewels and then finally, kilowatt hours. Usually when we talk about electrical bill, it's associated with kilowatt hours. So we're gonna stay here. Kilowatt hours equals 3.6 times 10 to the six jewels. So these are three conversion factors associated with R. S. I unit for energy. Also realize here that I didn't put purple boxes around them so usually are not expected to memorize them. They're oftentimes given to you within the question, or they're given to you on a formula sheet when taking an exam. But here just again. Remember these air three common types of conversion factors associated with jewels

Nature of Energy Example 1

here, it states which of the following statements deals with potential energy with non chemical energy associated with it. Remember, potential energy is just the energy of position, whereas chemical energy, which is an offshoot of potential energy, it's just associated with the chemical bonds of atoms. All right, so if we take a look here, it says a car traveling with the velocity of 51 m per second with a mass of 1250 kg. Here we're talking about velocity. We're talking about the motion of this car, so this is more associated with kinetic energy. So this is out next, your chemistry book, sitting on a table counter near the trash can weighing 12 Newton's at a height of 1.2 m, so make sure doesn't fall into the trash can here. They're just talking about the position of the chemistry book. Okay, it's at a certain height, and then we're talking about a force on it here. This is purely potential energy, so this would be our answer. But let's look at the other options. Ah, chunk of coal being thrown into a furnace to generate heat here. We're talking about heat being generated from this. This is closely related to thermal energy. And then next we have the warmth coming from a campfire. So again, we're talking about temperature. We're talking about heat. So this is a version of kinetic energy in the form of thermal energy. So out of all the choice is the only one that is purely potential energy. Without talking about chemical energy would have to be option B.

An energy efficient refrigerator uses 780 kWh of electrical energy per year. How many kilocalories of electricity does it use in three years?

• A. 2.0 x 10⁵ kcal
• B. 8.3 x 10⁵ kcal
• C. 2.0 x 10⁶ kcal
• D. 8.3 x 10⁶ kcal