HOMEWORK! for 3E2/3E3

do complete all the Questions in worksheet 1 and the worksheet 2
I have given you.

BY MONDAY, 2nd August 2010.

I'll collect on that day.


thanks

Molar Mass

Molar mass = mass of 1 mol of substance.

so how do I know the molar mass of substance??

Find the Ar in periodic table add a g behind.

TADAAH! you get your Molar mass for a particular atom.

Eg.

Molar mass of Cu = 64 g
Molar mass of N = 14 g

sooooooooooooo

If i ask you how many moles are there in 28 g of N?

remember 1 mol = 14 g of N
so

28 g of N = 28/14 = 2 mols

if i ask you how many moles are there in 32 g of Cu?

Ans: 1 mol = 64 g of Cu
32 g = 32/64 = 0.5 mol


FORMULA

number of mols = mass/ molar mass


Note:
molar mass of a molecule = Find the Mr add a gram behind.

Eg.
molar mass of CO2 = 12 + 2 X16 = 44 g

the mole!

okay.

AGAIN! we are not learning about the mole on your face but its a UNIT for particles (for example: atoms, molecules, ions)

SIMPLER EXAMPLE first!

1 dozens = 12 eggs

0.5 dozens = ?? eggs
answer: 6 eggs

NOW we have

1 mol = 6 x 10^23 particles

Question 1:
0.5 mol = ?? particles
answer: 0.5 of 6 x 10^23 particles
answer: 3 x 10^23


24 eggs = ?? dozens
answer: 2 dozens

Question 2:
1.2 x 10^24 particles = ?? mols
answer: 1.2 x 10^24 divided by 6 x 10^23
answer: 2 mols

CAN? always think in terms of dozens again if still confused.

Please please do your homework given.
WORKSHEET CHAPTER 8.3 Question 3-6 by monday, 26th July

in meantime, i still want to see your file!
get a ring file and put whatever notes i have given you since term 1 inside according to content page given to you.
only 4 ppl submitted to me.

I AM BACK!

okay.

I know this is very delayed but i finally managed to figure out my password after sooooo long.

-__-''

so, do visit often for anything about my lessons.

-ms shanti-