Question

Need help doing chem calc. Please help!

Additional Problems Show all work and calculations! 1. Identify the following as a weak electrolyte, strong electrolyte, or nonelectrolyte and write the equation for when they are in solution. Example: PbCl2 is a weak electrolyte PbCl2(s)く-) Pb2+(aq) +2 Cl-(aq) a. H2SO4 c. H3PO4 d. (NH4)3PO4 e. CH3C2OH f. Ba(OH)2 g. CH3CO2H h. HCI 2. Calculate the concentration of a solution in which 5.8 moles of NaCl are dissolved in 250 mL of solution'? 3. Calculate the grams of KNOs should be used to prepare 6.50 L of a 0.355 M solution? 4. Calculate the volume to be added to 5.0 g of KCI to prepare a 0.25 M solution?

Answer 1

1) Strong electrolyte

H2SO4(aq) + 2H2O(l) --------> 2H3O+(aq) + SO4^2-(aq)

HCl(aq) + H2O(l) ---------> H3O+(aq) + Cl-(aq)

Ba(OH)2(aq) --------> Ba2+(aq) + 2OH-(aq)

Weak electrolyte

H3PO4(aq) + H2O(l) <------> H2PO4-(aq) + H3O+(aq)

H2PO4-(aq) +H2O(l) <------> HPO4^2-(aq) + H3O+(aq)

HPO4^2-(aq) + H2O(l) <------> PO4^3-(aq) + H3O+(aq)

(NH4)3PO4(aq) <------> 3NH4+(aq) + PO4^3-(aq)

CH3COOH(aq) + H2O(l) <------> CH3COO-(aq) + H3O+(aq)

Non electrolyte

CH3CH2OH(aq)

C6H12O6(aq)

2) Concentration of solution = (5.8mole/250ml)×1000ml =23.2M

3) 0.355M = 0.355 mol per liter

for 6.5L no of mole of KNO3 = 6.5×0.355 = 2.3075

molar mass of KNO3 = 101.103g/mol

grams of KNO3 should be used = 2.3075mole × 101.103g/mol = 233.30g

4) Molar mass of KCl = 74.551g/mol

No of mol of KCl in 5g = 5g/74.551(g/mol)=0.06707mol

Volume to be added = (1000ml/0.25mol)×0.06707mol =268.28ml