Chemistry What is the mass of one mole of aluminum?

[AngelShare]

I have almost my entire worksheet done but I wanted to check my answers and get some help with the final question.

What is the mass of one mole of aluminum?
The mass of one mole of aluminum is 26.981 grams.

What is the mass of one mole of hydrogen?

1.008 g

What is the mass of one mole of carbon dioxide, CO2?

4.4009 x 10^1 g

What is the mass of one mole of sulfuric acid?

9.8079 x 10^1 g

How many moles in 3.00 g H2SO4?

.030 mol

How many moles in 12.0 g CH4?

.748 mol

How many moles in 3.40 x 10^1g CaO?

.606 mol

How many moles in 13.4 g SO2?

.21mol

What is the mass of 0.369 mol N2?

10.337 g

What is the mass of 10.0 mol Ca(NO3)2?

1641 g

What is the mass of 1.94 x 10^-3 mol C6H12O6?

.340 g

What is the mass of 0.0112 KCl ?

.840 g

How many particles in 25.9 mol Fe ?

1.56 x 10^25

How many particles in 0.30 mol NaCl ?

1.8 x 10^23

How many moles in 4.7 x 10^24 atoms Cu?

7.8

This is the one I need help with:

How many moles in 8.30 x 10^25 molecules H2O?

138
245
213
156

I hope I at least did the other ones correctly.

 

[Haxx0rm4ster]

Hi,

I saw a few of the first ones and they seemed right... sry, kind of lazy to check all of them.

for the last one


1 mole = 6.022*10^23 molecules ... in other words:

___1mole________________ = ___x-moles_____
6.022*10^23molecules_____8.30 x 10^25molecules


\

now solve for x just by multiplying 8.30*10^25
which gives you 137.8279641 moles.
Now, if you count sig. digits that would be 138 moles.

 

[AngelShare]

I don't blame ya, it's a wonder that I did them all myself.

How are you getting that? I'm a bit confused...I'm assuming, hopefully correctly, that you meant to put the 8.30 x 10^25 on the top, not the bottom? Otherwise, I'm lost.

 

[Haxx0rm4ster]

Its an equation. when you multiply 8.30*10^25 on both sides, the 8.30*10^25 on the right side cancels out and you put it on the left side too ( on top of the equation) then just divide, and as you see, molecules cancel out, leaving you with just moles.

Remember you are solving for the variable "x-moles"