You can get the definition of an acid from you text/notes/google.
For the HA problem. For pH = 3.50 convert to (H^+). I obtained approx 3E-4 but you need to confirm since that's an estimate.
.......HA ==> H^+ + A^-
E......x....3E-4...3E-4
Substitute the E line into the Ka expression and solve for (HA).
Then (HA) = M = mols/L. YOu have M and L, solve for mols.
Then mols = grams/molar mass. You have mols and grams, solve fo rmolar mass. Remember to use the real value for (H^+) and not my estimate.
Acids and bases
• What is an acid?
• A 500cm3 solution containing 1.9g of a weak acid HA has a pH of 3.50. Calculate the molar mass of the acid, given that it has a Ka of 2.0 × 10-6moldm-3
• Calculate the pH of the following:
• 0.002moldm-3 NaOH
• 0.30 moldm-3 NH4Br
• 0.001moldm-3 H2SO4
2 answers
By the way, the Ka value has no units and don't let anyone tell you they do. When they are used, most of the time they are called just units, but often they are called "tentative units". "temporary units", "trial units", or
1 answer