00:01
We are asked to use the information in the table that i've written right here to find the following information.
00:07
We are given an ion that has an unknown charge and we're told that the total mass of all the electrons, i'm going to abbreviate electrons, e minus, plus, and n neutral.
00:29
Electron mass total is equal to 5 .34 times 10 to the minus 23rd grams.
00:48
And the proton mass, i wrote the wrong one down here, my bad.
00:57
My electron mass is 2 .55 times 10 to the minus 26th grams.
01:06
And my proton mass total is equal to 5 .34 times 10 to the minus 23rd grams.
01:20
We're going to divide each of these by the mass per, by these masses right here.
01:32
I'm going to just convert these.
01:34
So 9 .19 times 10 to the minus 31st kilograms.
01:46
And then i'm going to go 1 ,000 grams per kilogram.
01:51
And this will equal, let me do my math.
01:57
Clear, clear.
01:57
2 .55 times 10 to the minus 26th divided by 9 .19 times 10 to the minus 31st.
02:08
Oops, see i got, got to clear the heck out of this.
02:10
2 .55 times 10 to the minus 26th divided by 1, 9 .1, 0 .19 times 10, 9 .109 times 10 to the minus 31st divided by 1 ,000 is 28 electrons.
02:39
Now let's figure out how many protons we have.
02:44
And we'll divide this by 1 .673 times 10 to the minus 27th kilograms times 1 kilogram per 1 ,000 grams.
03:01
5 .34 times 10 to the minus 23rd divided by 1 .673.
03:11
Is that right? 1 .673 times 10 to the minus 27th divided by 1 ,000 is 32 protons.
03:26
5 .34 times 10 to the minus 23rd divided by 1 .673 times 10 to the minus 23rd.
03:30
I just want to make sure i've got the right number.
03:37
1 .673.
03:45
What the heck happened to my, there we go.
03:54
So this will be, let me get to a p table here...