1a) A 250 mL container of CO2 exerting a pressure of 1.00 atm is connected through a valve to a 500 mL container of O2 exerting a pressure of 2.00 atm. When the valve is opened, the gases mix, forming a 750 mL mixture of CO2 and O2. What is the total pressure of this mixture?1b) Each molecule of hemoglobin combines with four molecule of oxygen in order to transport oxygen throughout the body. It is observed that 1.51 g of hemoglobin combines with 2.30 mL of O 2 at 37 °C and 743 torr. What is the molar mass of hemoglobin?

1a) For Boyle's Law, when a state change occurs without a change in the temperature, the product of the pressure by the volume remains constant. For Dalton's Law, the total pressure of a gas mixture is the sum of the partial pressure of the components. Then:

P1V1 + P2V2 = PV

Where P1 is the initial pressure of CO₂, V1 is the initial volume of it, P2 is the initial pressure of O₂, V2 is the initial pressure of it, P is the pressure of the mixture and V is the final volume of the mixture (V1 + V2).

1*250 + 2*500 = P*750

750P = 1250

P = 1.67 atm

1b) Let's call hemoglobin by Hem. The stoichiometry reaction is:

Hem + 4O₂ → HemO₂

So, let's calculate the number of moles of oxygen in the reaction, by the ideal gas law, PV = nRT, where P is the pressure, V is the volume (0.0023 L), n is the number of moles, R is the ideal gas constant (62.3637 L.torr/mol.K), and T is the temperature (37°C = 310 K).

743*0.0023 = n*62.3637*310

19,332.747n = 1.7089

n = 8.84x10⁻⁵ mol

For the reaction, the stoichiometry is:

1 mol of Hem -------------------- 4 mol of O₂

x ------------------- 8.84x10⁻⁵ mol of O₂

By a simple direct three rule

4x = 8.84x10⁻⁵

x = 2.21x10⁻⁵ mol of hemoglobin

The molar mass is the mass divided by the number of moles:

M = 1.51/2.21x10⁻⁵

M = 68,330 g/mol