molarity problem

[joonkimdds]

Advertisement - Members don't see this ad

How many grams of acetic acid(C2H4O2) would you use to make 10L of a 0.1M aqueous solution of acetic acid? (Atomic weights are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen)

a) 10g
b) 0.1g
c) 60g
d) 6.0g
e) 0.6g



help me plz~

 

[mld]

the answer is choice C.

 

[mld]

How many grams of acetic acid(C2H4O2) would you use to make 10L of a 0.1M aqueous solution of acetic acid? (Atomic weights are approximately 12 for carbon, 1 for hydrogen, and 16 for oxygen)

a) 10g
b) 0.1g
c) 60g
d) 6.0g
e) 0.6g



help me plz~

Molarity=Mol/Liters
Mol=(Molarity)(liters)=(0.1M)(10L)=1 mol acetic acid
1 Mol acetic acid=2(Atomic wieght of Carbon)+4(Atomic weight of hydrogen)+2(atomic weight of oxygen) = 2(12g) + 4(1g)+ 2(16g)= 24+4+32= 60grams
So you need to add 60 grams of acetic acid to 10 Liters of water to make a .1Molar solution of acetic acid.

 

[Dion]

Well, the problem gives you liters and moles per liter , which is the same as M (Molarity). You need to go to grams. First, you convert the given information into moles. You do that by multiplying the 10 L by 0.1 (mol/liter). This multiplication cancels out the liters and gives you moles of C2H4O2, which comes out to 1 mol. You want the answer to be in grams. In order to convert it into grams you multiply by the molar mass. 1 mol multiplied by 60 g/mol of C2H4O2 gives you 60 g.

 

[acetyl]

M = mols/liter

You want 0.1 M, and 10 L of solution, so you need 1 mol.

1 mol/ 10 L = 0.1 M

Then you need to find how many grams are in one mole of acetic acid.