Concentration

Concentration refers to the amount of solute in the solvent

Less than the max amount of solute in the solvent

Max amount of solute in the solvent

Temporarily more than a saturated solution. More than the max amount of solute in the solvent.

200 mL of distilled water is added to 4.00 g of a powdered drug to make a final volume of 3.00 mL. Calculate the percentage in a m/v %.

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A sample has a mass of 23.47 g. The solution was evaporated and the residue had a mass of 4.58 g. Calculate the m/m % of calcium chloride in the solution.

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Rubbing alcohol is sold as 70% (v/v). What volume of alcohol is used to make 500mL?

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Just like how % is parts per hundred, we use PpM and PpB when the ratio becomes very small

Does not refer to the particles per million/billion, but the mass of solute compared to the mass of the solution

The solubility of NaCl is of water. What is the concentration in ppm?

In chemistry, concentration is usually expressed in terms of molarity (M)

Where is molarity (), is the number of moles, and is the volume in litres

What is the molarity of a solution made by dissolving of in enough water to make of solution?

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of an aqueous solution of was added to sample of calcium carbonate () to produce calcium chloride (), with water and carbon dioxide as by-products, according to Reaction (1). All the reacted. The excess from Reaction (1) was used in Reaction (2) and reacted completely to produce of a barium chloride () solution.

What was the original concentration of used in this reaction?

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Summary: reacts with excess , then that excess is reacted with excess . Find original concentration of .

Equation 1:

Equation 2:

All together:

Dilution involves preparing a diluted solution from a more concentrated stock solution

Where is the molarity (mol / L), is the volume in litres, and the left side is the stock/concentrated solution

Pretty standard stuff

What volume of sodium sulfate solution would be required to prepare of sodium sulfate.

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Silver nitrate is a very expensive chemical.
For a particular experiment, you need of , but only of is available. You decide to pipette of solution into a flask, add an appropriate mass of , and then dilute the resulting solution to exactly . What mass of must you use?

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• We need of solution
• We have of
  • We use of

all together: