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General Chemistry

Learn the toughest concepts covered in Chemistry with step-by-step video tutorials and practice problems by world-class tutors

14. Solutions

Osmotic Pressure

Osmotic Pressure is the force that drives Osmosis from higher concentration to lower concentration.

Osmotic Pressure Calculations

Osmotic Pressure Concept 1

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now recall The osmotic pressure is the force that drives the movement of water from a lower concentration to a higher concentration. And remember that the osmotic pressure of a solution can be influenced by its concentration and temperature. So if we take a look here we have our osmotic pressure formula here. We're going to say the osmotic pressure, which is represented by this piloting symbol, is in units of atmospheres and it equals I, Which is your Van Hoff factor Capital M. Which is your molar? Itty or concentration or so liability. Okay. And that will be in moles per liter. So moles aside over leaders of solution Times are are is your gas constant, which is .08-06 leaders times, atmospheres over moles, times K. And then here finally t is our temperature and that would be in units of Kelvin. So just remember, when it comes to osmotic pressure, concentration and temperature can play a role in influencing the osmotic pressure of any solution

Osmotic Pressure Example 1

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here, it says. Calculate the osmotic pressure of the solution that is 18.30 mg of zinc oxide in 15.1 ml of solution at 26 degrees Celsius. Alright, so osmotic pressure equals I times polarity times r times T zinc oxide is an ionic solute that breaks up into zinc ion and oxide ion. That's two ions. So I equals two capital M is our polarity, which is moles over liters here. When I convert the 15 MLS into liters, that's 150.15 liters. Then I can change the 8.30 mg of zinc into moles. So remember, one mg is 10 to the negative three g and one mole of zinc, the weight of zinc oxide, the mole, the weight of zinc oxide. When we figure that out is Well, the masses 81 3, 8 g. So when we work that out, the moles is 2.2487 times 10 to the - moles. So then that's gonna give us our moles over liters or is R gas constant which we don't have to do anything. We just have to plug it in, And then our temperature needs to be in Kelvin. So add to 73.15 to this number here, and that gives us to 99.15 Kelvin. So then what cancels out Kelvin's? Cancel out moles, cancel out leaders, cancel out and we're left with atmospheres at the end. So we plug this in, we're gonna get as our atmosphere's . atmospheres as the osmotic pressure for this given solution.

The osmotic pressure of blood is 5950.8 mmHg at 41°C. What mass of glucose, C6H12O6, is needed to prepare 5.51 L of solution. The osmotic pressure of the glucose solution is equal to the osmotic pressure of blood.