Assuming that the solute consists entirely of nacl (over 90% is), calculate the osmotic pressure of seawater at 20∘c.

The osmotic pressure of seawater at 20∘c. = 3.12 atm

Osmotic pressure is the minimum pressure applied to the solution so that there is no osmotic transfer from a thinner solution to a more concentrated solution.

General formula:

π = osmosis pressure (atm)

M = concentration of solution (mol / l)

R = constant = 0.08205 L atm mol-1 K-1

T = Temperature (Kelvin)

The full question should be:

Seawater contains 3.8g of salts for every liter of solution.

Assuming that the solute consists entirely of NaCl (over 90% is), calculates the osmotic pressure of seawater at 20 degrees Celsius.

mole NaCl = 3.8 gram: 58.5 (molar mass of NaCl)

mole NaCl = 0.065

so the molarity = 0.065 M

For NaCl electrolyte solutions, the van't Hoff factor (i) is taken into account. And the value of i for strong electrolytes such as NaCl which has a degree of ionization = 1 then i = n = 2 (NaCl ionizes into 2 ions namely Na + and Cl-)

Temperature = 20° C+ 273 = 293 K

then

π = M. R. T. i

π = 0.065. 0.082. 293. 2

π = 3.12 atm

colligative properties

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Raoult's law

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The vapor pressure of benzene

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The freezing point of a solution

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Keywords: osmotic pressure, electrolyte solution

The question has missing information. At part 1 it is "Write a balanced chemical equation, including physical state symbols, for the decomposition of solid calcium carbonate (CaCO3) into solid calcium oxide and gaseous carbon dioxide."

Part 2. "Suppose 19.0 L of carbon dioxide gas are produced by this reaction, at a temperature of 290.0°C and pressure of exactly 1 atm. Calculate the mass of calcium carbonate that must have reacted (...)"

41.0 g

Explanation:

1. Calcium oxide has molecular formula CaO and carbon dioxide CO₂, thus, the reaction will be:

CaCO₃(s) → CaO(s) + CO₂(g)

The equation is already balanced because there's the same number of each element on both sides.

2. First, let's calculate the number of moles of CO₂ produced by the ideal gas law:

PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant (0.082 atm.L/mol.K), and T is the temperature (290°C = 273 = 563 K).

1*19 = n*0.082*563

46.166n = 19

n = 0.4116 mol

By the stoichiometry of the reaction:

1 mol of CaCO₃ 1 mol of CO₂

x 0.4116 mol

By a simple direct three rule:

x = 0.4116 mol of CaCO₃.

The molar mass of the calcium carbonate is 100 g/mol, thus the mass (m) is the number of moles multiplied by it:

m = 0.4116*100

m = 41.16 g = 41.0 g