Rate of dissolving

advertisement

Mixtures and

Solutions

Name ______________________

Teacher ____________________

Science Class Period 1 2 3 6 7

Date _______________________

Mixture - 2 or more substances mixed together but not chemically combined

Examples:

Granite – contains feldspar, mica, quartz among other substances

Sand

Soil

Tossed salad

Mixtures are classified according to how well mixed they are

Heterogeneous - substances in which components are not evenly distributed

Examples:

Vinegar and oil

Granola (oats, seeds, coconut, raisins, etc)

Homogeneous - substances in which the components are evenly mixed

Examples:

Paint

Milk

Toothpaste

Perfume

Mixtures can be classified as colloids, suspensions, and solutions.

Colloid - a mixture in which the particles are mixed but not dissolved.

The particles do not settle out.

The particles can be seen when a light is shined through the colloid.

Examples:

Paint

Fog

Smoke

Shaving cream

Suspension - a heterogeneous mixture in which some particles settle out

Example:

Raging river water- silt and particles drop out when water is still

Solution - well-mixed mixture in which the particles are small and dissolved

Examples:

Sea water. 70% of the Earth is covered with a salt water solution

Air is a solution of mostly nitrogen and oxygen

CO

2

is a gas dissolved in soda pop

Physical Science Series Mixtures and Solutions Video Notes 1

Solute - a substance that is dissolved in another substance.

Solvent - a substance in which the solute is dissolved

In sea water, salt is the solute and water is the solvent

Water is called the universal solvent because many substances dissolve in water

Soluble - ability of a substance to dissolve into another substance

Sugar is soluble in water.

Insoluble - inability of a substance to dissolve into a specific substance

Oil is insoluble in water.

Rate of dissolving:

Stirring speeds up rate of dissolving

Particle size- the smaller particles have more surface area that comes in contact with the solvent

Generally, increased temperature speeds the rate of dissolving a solid into a liquid.

Solubility - measure of how much solute can be completely dissolved in a solvent

A solvent can only dissolve so much solvent

Example:

Copper sulfate, CuSO

4

32 g/ 100 mL water at 20

C

Saturated solution - a solution that has dissolved all the solute it can at a specific temperature.

Label the x-axis

C.

Label the y-axis grams/100g of water.

Draw a curve that shows how much solute can be dissolved in the water at a specific temperature.

Above the curve, the solution is saturated. Below the curve, the solution is unsaturated.

Note: The graph below is not the graph from the video. Notice that the area above the red line shows where a solution is saturated. In other words, not all of the solute would be dissolved.

Some of the solute would settle to the bottom of the beaker.

Physical Science Series Mixtures and Solutions Video Notes 2

Warm lakes dissolve less oxygen, O

2

, than cold lakes.

Label the x-axis [O

2

].

Label the y-axis

C.

Draw a curve that shows how much oxygen, O

2, can be dissolved in the water at a specific temperature. Above the curve, the solution is saturated. Below the curve, the solution is unsaturated.

Alloys - a metal in which 2 or more solids are dissolved together

Example:

Steel, a solution of iron, chromium, and other metals

Sterling silver, a solution of silver, Ag, and copper, Cu.

Quiz:

1. A __ heterogeneous _____ mixture is not well-mixed.

2. A __ homogeneous _____ mixture is the same throughout.

3. In a colloid, the particles are _ mixed but not dissolved _.

4. Muddy river water is an example of a _ suspension ___.

5. In a solution the particles are _ dissolved ___.

6. The _ solvent ___is the part of the solution that does the dissolving.

7. __ Water ____ is often called the universal solvent.

8. The ___ solute ____ is the part of the solution that is dissolved.

9. __ Smaller ____particles tend to dissolve faster than larger ones.

10. An __ alloy ____ is a metal made of two or more solids.

Physical Science Series Mixtures and Solutions Video Notes 3

Physical Science Series Mixtures and Solutions Video Notes 4

Download