The distinctive odor of vinegar is due to acetic acid, HC2H3O2. Acetic acid reacts with sodium hydroxide in the following fashion: HC2H3O2(aq) + NaOH(aq) H2O(l) + NaC2H3O2(aq). If 2.79 mL of vinegar requires 34.9 mL of 0.1001 M NaOH to reach the equivalence point in a titration, how many grams of acetic acid are in a 1.00 qt sample of this vinegar? (1 L = 1.0567 qt)
g/qt
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Expert's answer
2018-02-24T08:05:08-0500
CH3COOH (aq) + NaOH (aq) H2O (l) + CH3COONa 1. Find chemical amount of sodium hydroxide(NaOH): 1000mL contains 0.1001 mole of NaOH; 34.9 mL contains x mole of NaOH; 1000/34.9 = 0.1001/x; x = 0.0035; n(NaOH) = 0.0035 mole.
2. The equivalence point in a titration is reached when substances react with each other in equivalent amounts. Find chemical amount of acetic acid (CH3COOH): According to equation 1 mole of acetic acid reacts with 1 mole of sodium hydroxide, i.e. n(CH3COOH) = n(NaOH); n(CH3COOH) = 0.0035 mole.
3. Find mass of acetic acid in 2.79 mL of vinegar: m = Mn; M(CH3COOH) = 122+14+162 = 60 (g/mol); M(CH3COOH) = 600.0035 = 0.21 (g).
4. Find m(CH3COOH) in 1.00 qt of vinegar: 1 L = 1.0567 qt; 2.7910-3 L = y qt; 1/2.7910-3 =1.0567/y; y= 0.0029 qt. 0.0029 qt of vinegar contains 0.21 g of acetic acid; 1 qt of vinegar contains z g of acetic acid; 0.0029/1 = 0.21/z; z = 72.41 (g/qt).
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