Question

The following substances are commonly found in commercial antacids. write the acidbase reaction resulting from the reaction with HC1. Note! Not all react in a 1:1 ratio! 1· Calculate the number of grams of HCI that could be neutralized by 500 mg of each substance in question #1 . Show your work. 2. moles Barney gawks at his iPhone to check the score of the game he bet a c-note on and accidentally misses the endpoint of the titration by going twenty six drops past it before he stops the flow of standard (31.74 mL) and does another trial. What percentage error was caused by the seven drops? (20 drops 1 mL). Show your work. Also, do not be a Barney! . solution through the buret. He records the volume measurement 1251 Erneriment 5

Answer 1

1)

a)

CaCO3 (s) + 2HCl (aq) -----------> CaCl2 (aq) + H2O (l) + CO2 (g)

b)

Mg(OH)2 + 2 HCl     -----------------> MgCl2 + 2 H2O (l)

c)

Al(OH)3 (aq) + 3 HCl (aq)   -------------> AlCl3 (aq) + 3 H2O (l)

2)

mass of each substanc = 500 mg = 0.5 g

a) moles of CaCO3 = 0.5 / 100 = 0.005

1 mol CaCO3   -------------> 2 mol HCl

0.005 mol CaCO3   ------------> ??

moles of HCl = 0.005 x 2 / 1 = 0.01 mol

mass of HCl required = 0.365 g

b)

moles of Mg(OH)2 = 0.5 / 58.32 = 8.57 x 10^-3

moles of HCl = 0.0172

mass of HCl = 0.626 g

c)

moles of Al(OH)3 = 0.5 / 78 = 6.41 x 10^-3 mol

moles of HCl = 0.0192

mass of HCl = 0.702 g