 ## General Chemistry

Learn the toughest concepts covered in Chemistry with step-by-step video tutorials and practice problems by world-class tutors

20. Electrochemistry

In voltaic/galvanic cells electrical current is created, while in an electrolytic cell electrical current is consumed to drive the reaction.

The Ampere

The ampere or amp represents the SI unit for electrical current and represents charge per second.

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example

## Amperes & mass 3m
Play a video:
Hey, guys. So here we're talking about the concept of electrical current, So when we say electrical current, another term for it would be amps or amperes. I'm going to stay here current or am Saran Piers. It's really just charge. Over time, we're gonna stay here, charge we use sea to represent columns and time here would be in seconds. So knowing this is key to get answering these questions. So for the first one, it says gold can be plated out of a solution containing gold three based on the following half reaction. So here we have gold. Three ion reacting with three moles of electrons to give us one mole of gold solid here were asked what massive gold that's played it out by a minute flow of 6.8 amperes or current. All right, so they're asking us to figure out the mass of gold realize here when they say 6.8 a that represents and peers. So this were really represents 6.8 cool ums per one second, because again, amperes amps is cool times per second now because this has seconds in it. That means that we have to convert the minutes given to us in two seconds as well. So we're gonna start out with the minutes. We have 41 minutes. We're going to stay here for every one minute. It comes down to 60 seconds. Now that we have seconds, we can cancel out the second in the apse. So it's 6.8 columns for one second. And where do we see columns? We see cools with Faraday's constant Faraday's constant, which is F So Faraday's constant is 96,000, 485 cool ums per one mole of electrons. So we want to cancel out. Cool. Um, we're gonna put 96,045 columns on the bottom so they can cancel out That's equal toe one mole of electrons. Now, if we take a look at this equation for every one mole off gold, there are three electrons involved. So we're gonna say for every one mole of gold solid, there are three moles of electrons involved, So moles of electrons cancel out. Now that I have mobile electrons, I can change that into grams. So for every one mole of gold, it's mass. On the periodic table is 1 96.97 g for gold. So we have at the end of grams of gold, which comes out to 11.38 g of gold. So that will be our final answer here. And remember, current is just charged over time and other words for it amps and peers or just a
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example

## Electrical Current 2m
Play a video:
here, it states. Ah, solution of mag unease five is used to play out maga knees and electrochemical cell. If a total of 1.13 g of mag unease is played it out in a total time of 1600 seconds. What was the electrical current used? So remember, electrical current is the same thing as amps or am Pierce, Remember Here this is just columns per second. So we need to find columns and divide them by the total number of seconds. We already know the total number of seconds in the question. We have 1600 seconds totalled so 1600 seconds along the bottom. All we have to do now is figure out the amount of columns we have to do that. We're going to start out with 1.13 g of mag unease given. So we have 1.13 g of mag unease. We're going to stay here for every one mole of manganese. We're told that it's mass. Is this 54.94 g so those can't slapped Now We're going to stay here for every one mole of mag unease. How many moles of electrons do we have involved where we're going from, plus five to neutral mag unease. So that means we're dealing with five moles of electrons. So moles, um, agonies cancel out. Now we have five moles of electrons. And now that we have most of electrons, we can use Faraday's constant. So that's one mole of electrons is 96,485 cool apps. So most of electrons cancel out now, have columns. When I punched this in, this gives me 9922.47 cool apps. So take that and plug it up here. So we divide that by 1600 that gives us 6.20 amps, or amperes. So that will be our final answer for the amount of electrical current
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example

## Electrochemistry & Voltage 4m
Play a video: 