Mixtures and Solutions

What is “Matter?”

Anything that has mass and takes up space or volume

What is matter made of?

Very small particles too small to be seen.

What is the word that means “too small to be seen?”

Microscopic

Describe the property of a solid.

Solids have a definite shape and volume

Describe the particles in a solid.

Particles in a solid are very close to one another and

vibrate, but stay in the same place.

How can you measure the volume of a solid that has measurable

sides?

You can calculate the volume of a solid with rectangular sides by

measuring with a ruler and calculating the height x width x

length.

How do you measure the volume of a solid with irregular sides?

Measure the volume of an irregularly shaped solid by water

displacement in a graduated cylinder. The volume of water

displaced equals the volume of the object.

Describe a liquid.

Liquids have a definite volume, but their shape changes

according to the shape of their containers.

Describe the particles of a liquid.

The particles are still relatively close to one another, but they do move apart from each other and flow from place to place.

How do you measure the volume of a liquid?

You measure the volume of a liquid in a graduated cylinder or

syringe.

Describe the properties of gases

Gases have no definite shape or volume, but take the shape and volume of their containers

filling the space available.

Describe the particles of a gas.

The particles easily move far apart from each other and spread out through the available space.

How do you measure the volume of a gas.

You measure the volume of a gas in a graduated syringe.

What are mixtures?

Mixtures are composed of two or more substances that are mixed

together, but can easily be separated from each other.

What happens to the substances in a mixture?

the substances in a mixture do not permanently change in the mixture,

but they keep their separate properties

What are solutions?

Solutions are composed of substances that mix so

completely that they cannot be distinguished as separate

substances.

Can solutions be separated?

They can be easily separated back into the separate

substances.

What is the difference between a mixture and a solution?

A solution is usually a mixture of a solid that dissolves completely

in a liquid, for example salt or sugar in water.

What is an alloy?

Alloys of two or more solid metals that mix completely for example brass made from a mixture of

copper and zinc can be called a solution. The separate

substances mix so completely that they cannot be distinguished.

How can a mixture or solution be separated?

Mixtures and solutions can be separated by the processes of

filtration, sifting, magnetic attraction, evaporation,

chromatography.

How do you use filtration to separate mixtures?

Filtration is used to separating solid particles from a liquid by pouring the mixture through a

filter paper in a funnel. The filter paper traps the solid particles

and only allows the particles of the liquid to pass through.

When would you use this method?

This method is used, for example, in water treatment

plants as part of the process for separating dirt and other solid

particles from water to produce clean drinking water.

What is sifting?

Sifting is used to separate smaller solid particles from larger solid particles. The

mixture of different sized solid particles is put into a container that has a screen material at the bottom with holes of a

certain size. When the mixture is shaken, the smaller particles go through the

screen leaving the larger particles in the container.

When would you use sifting?

Cooks, for example, sift flour to get a small particle size for baking leaving

larger particles of flour in the sifter above the screen. Sand and gravel companies, for example, separate rocks into different sized particles for road building and other construction projects using this method.

What is magnetism?

Magnetic attraction is used to separating magnetic material

from a mixture of other substances. When a magnet is stirred through the mixture, it

pulls out the magnetic material from the mixture.

When is magnetism used to separate?

A “cow magnet”, for example, is given to a cow to swallow. It

stays in the first stomach of the cow keeping magnetic materials

like wire and other harmful materials that cows swallow from

going into the rest of their digestive system.

When is evaporation used to separate?

Evaporation is used to separate a solid that has dissolved in a liquid

solution.

How is it used?

The solution is heated until all the liquid turns to a gas (evaporates)

leaving the solid behind.

How could evaporation used in real life?

Salt in salt water or ocean water, for example, is separated by

heating the solution until all the water evaporates leaving the

solid salt in the container.

What is Chromatography ?

Chromatography is used to separate and analyze the solutes

(5-4.5)in a solution.

Describe chromatography.

A small amount (2-3 drops) of the solution is put on a piece of filter paper, which is put in a solvent (5-4.5). The substances in the solution, called

solutes (5-4.5), that dissolve most easily travel the furthest; and substances that do not dissolve easily do not travel very far. The bands of

color that are formed, for example, allow scientists to identify the substances in the solution by comparing them to the location of known

substances forming bands of color on different filter papers.

How is floatation used in separation?

Floatation is used to separate solids, which float from remaining

liquids in a mixture.

Describe how its used.

The solids are stirred and when they float to the top, they are

skimmed off the surface of the liquid and put into a different

container.

Give a real life example of how this is used.

This method is used, for example, in some water

purification plants. Students must be able to

separate mixtures using the procedures necessary for each

type of separation.

What is a solvent?

in a mixture that is a solution the substance that is in the greatest amount is the solvent, and it is

usually the liquid.

What is a solute?

The substance in the least amount is the solute and it is also usually the

solid.

What is a concentrated solution?

A concentrated solution contains a greater amount of solute than a

solution that is not very concentrated. The greater the

concentration of the solution, the greater the amount of solute is in

the solution.

What determines the relative concentration of a solution?

The ratio of solute to solvent determines the relative

concentration of a solution.

What is the rate of dissolving?

solids (solutes) dissolve in solvents (liquids) in solutions in

different amounts in given times,

What does the rate of dissolving depend on ?

Temperature, particle size, stirring,

How does temperature change the rate of dissolving?

If the temperature increases, more of the solute will dissolve

faster.

How does particle sizes change the rate of dissolving?

Usually, if the particle sizes are smaller, more of the solute will

dissolve faster.

How can stirring change the rate of dissolving?

Stirring can change the rate of dissolving. Usually, if the solution is stirred, more of the solute will

dissolve faster.

What happens when the substances are combined

chemically?

The new substance formed cannot easily be separated into

the original components.

Do chemically combinations have the same characteristics

as the original substances?

When substances chemically combine, a new substance is

formed that does not have any of the characteristics of the original substances that were mixed to

form it.

What happens when the substances combined are not

chemically combined?

When substances are mixed without being chemically

combined, a new substance is not formed, and the substances

can be easily separated.

How do pollution and harmful substances in our environment

occur?

Pollution or harmful substances in our environment result from the mixing and dissolving of foreign

substances in water, air, and soil.

What activities produce pollution?

These harmful substances are often produced as a result of

activities associated with industry, agriculture, burning

fossil fuels, or other processes associated with human activities.