Chem 108Expt #11: Efficiency of Antacids

Practice Problem from p.99

How to Complete the Calculations for Your Experiment

You will get a zero for the experiment if you are unable to complete the calculations. Start early so you can get help if necessary! 1

2

simulated stomach acid

neutralized by the antacid

to be neutralized by NaOH

# mol HCl = # mol HCl _ # mol HClneutr by antacid in stomach acid neutr by NaOH

The key to these calculations is to remember these 2 important relationship:

2) # moles = V x M

where V = volume in liter (L)

M = molarity in moles/liter (mol/L)

LEARN THIS NOW!!3

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3

1 L NaOH soln 0.400 mol NaOH# mol NaOH = 8.00 mL NaOH soln x x

1 L NaOH soln10 mL NaOH soln

= 0.00320 mol NaOH

3

1 L HCl soln 0.500 mol HClOriginal mol HCl = 50.00 mL HCl soln x x

1 L HCl soln10 mL HCl soln

= .0250 mol HCl (in simulated stomach acid)

2HCl + NaOH H O + NaCl

# mol NaOH = # mol HCl

# HCl neutr by NaOH = 0.00320 mol HCl

# mol HCl = 0.0250 mol HCl 0.00320 mol HCl =

neutr by antacid (in stomach acid) (neutr by NaOH)

0.0218 mol HCl

(neutr by anta ) cid