Question

1a) An Alka-Seltzer tablet contain 1.9 g of sodium bicarbonate (NaHCO3, MW 84.0) What is the potential volume of CO2 in mL produced by this pill at 35 degree Celcius (Body temp) and atmospheric pressure if all of its bicarbonate is converted to CO2?

b) A 0.5-L sample of air at 20 degree Celcius and 1.5 atm of pressure is heated to 100 degree C while keeping the volume unchanged. What is its overall pressure after this heating?

c) Explain in terms of the Kinetic Molecular Theory why it doesnt matter what the gas is- we can still use the ideal gas law. They key question here is why a gas like argon (MW 40) behaves essentially the same as helium (MW 4.0) in terms of the relationship between number of molecules and pressure given concentration and temperature. What is going on there?

Dont forget to Convert Celcius to K

Answer 1

Q1

m = 1.9 g of NaHCO3

mol = mass/MW = 1.9/84 = 0.02261 mol of NaHCO3

find volume of CO2 at T = 37°C = 310 K

so..

ratio is 1:1 mol of NaHCO3 : CO2

P V= nRT

V = nRT/P

V = (0.02261)(0.082)(310)/(1 = 0.574746 Liters

b)

V = 0.5 L

T = 20|C = 293 K

P = 1.5 atm

T2 = 100°C = 373 K

V = 0.5 L

P1/T1 = P2/T2

P2 = T2/T1*P1 = (373/293)(1.5) =1.909 atm

c)

we can assume this since we talk about "molecules" which we assume, ideally, that they are "points" and have no volume, and their mass is too low...

for concentration:

PV = nRT

moalr concentration = mol/L = n/V

so

n/V = P/(RT)

meaning that concentration depends on pressure and T