Question 1 A single dose of a certain antacid contains 250. mg of Mg(OH)2 and 30

Question

Question 1

A single dose of a certain antacid contains 250. mg of Mg(OH)2 and 300. mg of CaCO3. How many mmol of H+ can be neutralized by one dose of this antacid? Do not include units in your answer.

Question 2

What step is used to break the HCO3-/CO2 buffer system during the titration with NaOH?

Question 3

A 0.500 g antacid tablet is mixed with 50.00 mL of 0.100 M HCl then boiled. After cooling, 4.90 mL of 0.100 M NaOH is required to achieve a phenolphthalein end point. Calculate the neutralizing power of the antacid tablet in terms of mmol of H+/g of antacid. Do not include units in your answer.

Question 4

If calcium carbonate is the only active ingredient in the antacid in question #3, how many mg of calcium carbonate are there in a 0.500 g tablet? Do not include units in your answer.

Explanation / Answer

Answer 1

Write the equation first.
Mg(OH)2 + 2H+ ====> Mg2+ + 2H2O
CaCO3 + 2H+ =====> Ca2+ + CO2 + H20

So, from 1 moles of Mg(OH)2, 2 moles of H+ are neutralized.
Moles of Mg(OH)2 = mass in grams / Mr
Mass in grams= 250 mg

moleclar weight of Mg(OH)2 = 58.3197 g/mol

Find the moles and multiply by 2 to find the moles of H+ used up.

moles = weight / moleclar weight = 250 / 58.3197 = 4.2867
H+ used up =  4.2867*2 =8.5734
Find the moles of CaCO3 and again multiply by 2 to get moles of H+ used up.
moles = weight / moleclar weight = 300/100.0869 = 2.997 approx 3

H+ used up ==3*2 = 6

Add the two answer to get the total number of moles of H+ used up.
6+8.5734 = 14.5734

Answer 2

Adding excess HCl then boiling

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