1.Calculate the mass of KHC 8 H 4 O 4 (molar mass = 204.44g/mol) that reacts wit

Question

1.Calculate the mass of KHC8H4O4 (molar mass = 204.44g/mol) that reacts with 15mL of NaOH solution in part A.3. Express this mass of KHC8H4O4 to the correct number of significant figures and record the calculation on the report sheet. The molarity of NaOH is 0.16M

2. A 0.204g sample of CO32- antacid is dissolved with 25.0mL of 0.0981M HCl. The hydrochloric acid that is not neutralized by the antacid is titrated to a bromophenol endpoint with 5.83mL OF 0.104M NaOH. Calculate the number of moles of base in the antacid.

Explanation / Answer

1. The reaction for this problem is:

KHC8H4O4(aq) + NaOH(aq) = KNaC8H4O4(ac) + H2O(l)

Information:

1) Calculate the moles present in 0.015L of the 0.16M NaOH solution using the equation:

n = M*V

n NaOH = (0.16 mol/L)*(0.015L)

n NaOH = 0.0024 moles

2) Since the coefficients in the chemical reaction are 1:1, this means that 1 mole of NaOH requires 1 mole of KHC8H4O4 to react, so we can say that:

n KHC8H4O4 = n NaOH

n KHC8H4O4 = 0.0024 moles

3) Convert those moles to mass using the formula:

g = n*MM

Where g = grams, n = moles and MM = molar mass (204.44 g/mol).

g KHC8H4O4 = 0.0024mol(204.44 g/mol)

g KHC8H4O4 = 0.49g (two significant figures)

Answer: 0.49g KHC8H4 react with the NaOH solution.

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