3.7 Solutions and Mixtures + 3.8 Representations of Solutions + 3.10 Solubility

Solutions are sometimes called:

Homogeneous mixtures

What states can solutions be?

Solid, liquid, or gas

Do macroscopic properties vary throughout a solution?

No

In a heterogeneous mixture, the macroscopic properties depend on:

Location in the mixture

Solution composition can be expressed in one/multiple way(s)

Multiple

What is the most common method to express solution composition in the laboratory?

Molarity

Molarity = ?

Moles of solute / liters of solution

Can a solution involve solids?

Yes

Examples of solid solutions:

Steel and brass

Can a solution involve liquids?

Yes

Example of liquid solutions:

Mixture of ethanol and water

Can a solution involve gases?

Yes

Example of gas solution:

Air/atmosphere

A common example of a solution is one in which:

A substance is dissolved completely in water

A solution in which a substance is dissolved completely in water:

Aqueous solution

How many main ways are there to prepare an aqueous solution?

2

2 main ways to prepare an aqueous solution:

Dissolve a solid solute in water, or perform a dilution

What is combined in dilution?

A concentrated solution with water

What is created in dilution?

A dilute solution

A concentrated solution is often referred to as a:

Stock solution

What are the steps to dissolved a solid solute in water? (2.50g CuSO4.5H2O, 100 mL volumetric flask)

1. Turn on weighing balance

2. Put weighing paper on weighing balance 

3. Tare balance by pressing 0 button

4. Wear gloves and goggles

5. Scoop 2.50 g of CuSO4.5H2O using a spatula and weigh until reach the balance shows 2.50 g has been reached

6. Pour all of it into the 100 mL volumetric flask through a funnel by holding and lifting sides of weighing paper

7. Squeeze water from the distilled water wash bottle into the volumetric flask through the funnel until the bulb area is filled

8. Seal the volumetric flask with the lid

9. Shake and invert the volumetric flask to dissolve solute 

10. Squeeze even more water until the lower meniscus reaches just below the calibration mark

11. Squeeze water from the distilled water wash bottle into a small beaker

12. Insert the pipette pump onto the 1 mL pipette

13. Use the pipette and pump to extract water from the small beaker 

14. Use the pipette pump to displace the water from the pipette drop wise into the volumetric flask until the lower meniscus touches the calibration mark on the volumetric flask

15. Close flask with the lid

16. Shake and invert the final solution in the volumetric flask to ensure that it is homogeneous

17. Label the volumetric flask with “0.1M 100 mL CuSO4.5H2O” and you and your groupmates’ names

18. Wash hands with soap

How to perform a dilution? (10 mL 0.5M CuSO4.5H2O from 0.1 M of that)

1. Wear gloves and goggles

2. Take out the 0.1M CuSO4.5H2O 

3. Label the three test tubes as 0.05 M

4. Put a pipette pump on the volumetric pipette

5. Use the pump on the volumetric pipette to measure 5 mL of CuSO4.5H2O as precisely as possible

6. Pump out the measured 5 mL of CuSO4.5H2O from the volumetric pipette into the test tube labelled 0.05 M

7. Squeeze distilled water from the wash bottle into a small beaker

8. Pump up 5 mL of distilled water from the wash bottle using the volumetric pipette

9. Fill the test tube labelled 0.05 M with the 5 mL distilled water 

10. Wash hands with soap

What do particulate representations of solutions communicate?

Structure and properties of solutions

How do particulate representations of solutions communicate the structure and properties of solutions?

By illustration of the relative concentrations of the components in the solution and drawings that show interactions among the components

Which substances tend to be miscible or soluble in one another? 

Substances with similar intermolecular interactions