A scientist looking to remove oxygen from above a liquid sample pumps nitrogen into a sealed compartment to displace the oxygen, then places his liquid sample into the compartment. If the nitrogen pressure (partial pressure) was 1.8 atm, what would be the concentration of dissolved nitrogen gas if the Henry’s Law constant for nitrogen gas was 6.8 × 10-4 M atm-1 at this temperature?

1.2 × 10^-3 M

Explanation:

Henry's law law states that; once the temperature is constant, the amount of a given mass of gas that is dissolved in a particular type and volume of solvent is directly proportional to the partial pressure of that gas in equilibrium with the solvent.

From Henry's law;

Cg= K × Pg

Where;

Cg = concentration of gas

K= constant of Henry's law

Pg= partial pressure of the gas

Cg= 6.8 × 10^-4 M atm^-1 × 1.8 atm

Cg = 1.2 × 10^-3 M

confused

confused             hewdejdnjnjsnd

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol