Agata Łuszczyńska 23.01.2008

Batory High School

I IB

Investigate the solubility

of the salts

	Design
Asp1
Asp2
Asp3

Solubility is a physical property referring to the ability for a given substance, the solute, to dissolve in a solvent. It is measured in terms of the maximum amount of solute dissolved in a solvent at equilibrium (state in which the chemical activities or concentrations of the reactants and products have no net change over time ). The resulting solution is called a saturated solution. Solubility is meassured for 100g of solvent and it's units are grams per 100g of solvent (usualy water).

Solubility depends on many variables:

• the dissolved substance

• the solvent

• temperature

• pressure

• polarity of the solvent

I concentrated on the aspect of temperature and researched how the rise of temperature will affect the solubility.

Variables:

Independent:

• temperature

Dependent:

• amount of dissolved substance (NaCl)

Controlled:

• quantity of solvent (H₂O)

• pressure (1013 hPa)

Equipment:

• bunsen burner

• probe

• termometer

• scale

Reagents:

• sodium chloride (NaCl)

• water (H₂O) 50 ml

I will heat up a fixed amount of water (50 ml) up to temperatures: 40°C, 60°C and 80°C and dissolve NaCl in each temperature up to the point where the salt no longer dissolves. That is called the saturation point and indicates if the solution is saturated. Then I will meassure how much of NaCl I dissolved, make a proportion and calculate how much of the salt could dissolve in 100 ml of water (since the density of the water is 1g/cm³ 100ml of water weight 100g) and the amount that I will calculate equals to the solubility of the salt. Each trial I will do three times to ensure myself with the result.

The best way to collect the data will be a table:

Temperature [°C]	Quantity of the dissolved salt
Number of trial	1	2	3
40
60
80

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