AP Chemistry 3.3 Laws of Thermodynamics

AP Chemistry 3.3 Laws of Thermodynamics. How much energy would be required to completely melt the ice?

APAP Chemistry
AP ChemistryLaw of Thermodynamics
Laws of Thermodynamics
The Laws of Thermodynamics
LanguageEnglish Language
Test PrepAP Chemistry

Transcript

00:22

To cool iced tea, the ice cubes must melt.

00:25

How much energy would be required to completely melt 60.0 g of ice at 0 °C?

00:31

The heat of fusion for ice equals 6.01 kJ/mol.

00:36

And here are your potential answers.

00:39

All right, for the quantitative part of this problem, we need to think about water. [Person using a calculator]

00:43

Ah, so peaceful…

00:44

…Darn it.

00:45

Now we need a bathroom…[Toilet flushes]

00:47

Okay, where were we?

00:48

Oh, yeah, science.

00:50

Great.

00:51

So, we're given a heat of fusion, which is the amount of energy needed to melt one mole

00:54

of ice at 0°C.

00:55

To calculate the amount of energy needed to melt 60 grams of ice, we have to convert this [Robot shoots a laser and melts ice cubes]

01:01

weight to moles using the molecular weight of water.

01:04

Now we can just multiply the number of moles of ice by the heat of fusion to calculate

01:08

the overall heat, Q.

01:10

This question is a great example of why units are your best friend… [Boy juggling with measurement units]

01:13

Sorry, dogs.

01:14

You've been demoted.

01:16

By looking at the units of our answer and the information that we’ve got, we can deduce

01:19

the equation that should be used.

01:21

This is a great trick for when you’re unsure or just want to double check. [Girl scribbling in class]

01:25

It's also just a great party trick in general…y'know, if your thing is getting uninvited to parties. [Boy at a party with 3 upside down red cups]

01:30

Anyway, we can see that the correct answer is choice C, - 20 kJ.

01:34

All right, Fido, you can come back now.

01:37

We’re ready to play. [Boy shouts for Fido to come play]

01:39

Fido?

01:40

Where are you?

01:41

We were just kidding about that best friend thing… [Fido on the sofa reading a newspaper]