Water C 3 Flashcards pp. 58-65

Use the charts on pg. 62 to answer some of these questions.

At what pressure is the solubility of oxygen 8 mg in 1000 g of water?

1 atm

State the relationship between pressure and the solubility of oxygen.

As pressure increases, the oxygen becomes more soluble (more dissolves).

What is the relationship between temperature and dissolved oxygen?

As temperature increases the amount of dissolved oxygen decreases.

If you have 8 mg of O2 at 20oC, in 1000g of H2O, is the solution saturated, unsaturated or supersaturated?

unsaturated

What mass of O2 gas will dissolve in 1000g of H2O at 20oC?

9 mg of O2

In the Solvents lab, what solutes dissolved in hexane?

Iodine, I2 Propanol, C3H7OH Napthalene, C10H8

Why does a soda lose its “fizz” as it warms up?

The carbon dioxide gas is less soluble at higher temperatures.

What mass of O2 gas can be dissolved in 850g of H2O at 4 atm?

4 atm = 32 mg 32mg = __X__ 1000g 850g X = 27.2 mg O2

What is the minimum amount of H2O needed to dissolve 2 mg of O2 gas at 10oC?

At 10oC: 11mg =__2__ 1000g Xg X = 181.8g of H2O

What does “like dissolves like” mean? Give an example.

Polar substances dissolve in. polar substances. Non-polar substances Polar substances dissolve in polar substances. Non-polar substances dissolve in non-polar. Ex: Napthelene (moth balls) dissolved in hexane because they are both non-polar. Water and oil don’t dissolve since the water is polar and oil is non-polar.

In the Solvents lab what solutes dissolved in water?

Urea- CO(NH2)2 Ammonium Chloride- Urea- CO(NH2)2 Ammonium Chloride- NH4Cl Sodium Chloride- NaCl Propanol- C3H7OH Copper Sulfate- CuSO4