What volume of CO2 gas at 1.24 atm and 311 K would be formed when 10.0 mL of 1.0 M HCI is mixed with excess NaHCO3?

Question

Some antacids contain the base sodium bicarbonate, NaHCO3, which reacts with hydrochloric acid in the stomach to yield sodium chloride, carbon dioxide and water.

Answer 1

Hello, Elcy,

There are a lot of steps involved: predicting products, balancing the equation, calculating moles of CO₂, and adjusting the volume for non-STP conditions with the gas laws. Too much to write in detail. If you aren't clear on a step, please ask.

The balanced equation:

HCl + NaHCO3 = CO2 + NaCl + H2O

Convert the 10ml of 1.0 M HCl to moles HCl: (0.010 L)*(1.0 moles/liter) = 0.010 moles HCl.

The balanced equation says we'll get 1 mole of CO2 for every 1 mole of HCl (The NaHCO3 is in excess). So we will produce 0.01 moles of CO2.

For some reason unbeknownst to any sane person, the CO2 was collected at 1.3 atm and 311K. Use the ideal gas law to calculate volume under these conditions:

PV=nRT, where n is moles and R is the gas constant. I don't have the time to enter all the calculations, but I did select the gas constant, R, with the compatible units for the data here: R = 0.082058 L*atm/(K*mole). I arrived at 0.1963 liters, or 196 ml.

A lot of work for an unpopular gas.

Bob