# Factors Affecting Solubility

Batuan Colleges Inc.
17. Feb 2021
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### Factors Affecting Solubility

• 2.  refers to the maximum quantity of solute that can dissolve in a given quantity of solvent at a given temperature. The variation of solubility for compounds is dependent on several factors.
• 3. Objective: To investigate the effect of temperature on the solubility of sugar in water. Materials: 100 ml of distilled water, sugar, hot plate or Bunsen burner, spatula and thermometer.
• 4.  Procedure: › 1. Measure 100 ml of distilled water at room temperature and record its temperature. › 2. By using a spatula, add sugar in a small amount at a time to the water while stirring the solution after each addition of sugar, until the sugar no longer dissolves. › 3. Heat the solution to 50*C. Record your observation. Add more sugar to the solution until the sugar no longer dissolves. Stir after each addition. › 4. Repeat step 3 at 60*C and 70*C . Record your observations.
• 6.  Solids don’t dissolve very well in cold water as much as hot water does.  The hotter the water, the faster solids will dissolve in water  Solids increase solubility as temperature increases.(most of liquids expect for Na2SO4 and Ce2(SO4)3
• 7.  Objective: To determine the effect of temperature on the solubility of gases.  Materials: Dark colored soda, three 1 mL test tubes with stoppers, beakers, graduated cylinder, water at room temperature, ice-cold water, and hot water
• 8.  Procedure: › 1. Fill at least half of three test tubes with the same amount of soda. Put a stopper in the test tube. › 2. Prepare three water baths: cold, room temperature, and hot (not higher than approximately 40*C). › 3. Invert a cork-screwed test tube in each water bath. Observe the rate of bubble formation in each beaker. Note also the amount of gas at the top of each test tube.
• 9.  In which test tube is the rate of bubble formation the fastest? the slowest?
• 10.  The solubility of Gas in water decreases as the temperature increases.  The solubility of Gas in water increases as the temperature decreases
• 11. Objective: To investigate the effect of pressure on the solubility of gases. Material: An unopened plastic bottle of carbonated drink.
• 12.  Procedure: › 1. Take the bottle of carbonated drink and try to squeeze it. Observe how the bottle feels. Observe also the rate of bubble formation. Record your observations. › 2. Carefully open the bottle and let the gas escape. Reseal the cap and try to squeeze the bottle again. Now, observe the rate of bubble formation. Record your observations.
• 13.  When carbonated drinks are bottled, they are pressurized; that is why they are hard to squeeze. Pressurizing the bottles prevent the carbon dioxide from escaping the solution. The solubility of a gas in a liquid is proportional to the pressure of the gas over the solution. This relationship between gas solubility and pressure is known as Henry’s Law, which was formulated by an English Chemist named William Henry in 1803. The mathematical statement is given by: c=kP
• 14.  c is the molar concentration (mol/L) of the dissolved gas,  P is the pressure (in atm) of the gas over the solution,  And k is the constant for the given gas- where k depends mainly on the temperature, and has the units mol/L.atm
• 15.  Sample Problem: › Calculate the molar concentration of nitrogen in water at 25*C for a partial pressure of 0.78 atm. The Henry’s Law constant for nitrogen at this temperature is 6.8X10^-4 mol/L. atm. › Using the equation: › C=kP