Formic Acid (1.0M)-Sodium Formate (68.01 g/mol) Paragraph from page 4: Prepare 0
ID: 492392 • Letter: F
Question
Formic Acid (1.0M)-Sodium Formate (68.01 g/mol)
Paragraph from page 4:
Prepare 0.10 M solutions with volumes of 100mL of both the assigned acid and it's base. For most of the acids this will involve diluting a 1.0M solution of the acid. For most of the bases this will involve adding the appropriate mass of the base to a 100mL volumetric flask and diluting to mark.
Explanation / Answer
To prepare one L of 1M stock solution of both acid and conjugate base
1L of 1M formic acid stock solution
Molar mass of formic acid HCOOH = 46g/mol
molarity = number of moles /V(L)
= (46g/46g/mol) /1L = 1 M
Thus dissolving 46g of formic acid in 1 L of solution gives 1M solution.
!L of 1M sodium formate solution
molar mass of sodium formate = 68.01g/mol
Molarity = (68.01g/68.01g/mol ) /1L
= 1M
Thus dissolving 68.01 g in 1 L solution gives 1M sodium formate.
Part II
preparation of 0.1M solution of acid and conjugate base
V x1M = 100mL x 0.1M
thus V = 10mL
Thus diluting 10mL of 1M stock solution into 100mL gives 0.1M solution.
(same for both acid and sodium formate)
Mass required to make 100mL of 0.1 M solution
For acid solution
mass = molarity x molar mass x V(L)
= 0.1mol/L x46g/mol x0.1L
= 0.46g
similarly mass of sodium formate in 100mL of 0.1M solution
= 0.1mol/L x 68.01g/mol x 0.1L
= 0.68g