Pure Substances & Mixtures

Created by J_Smith127 

Upgrade to
remove ads

57 terms · Chapter 2-Section1

chemistry

the study of matter and its changes

Chemists explore

the makeup, properties, changes, and interactions of matter

anything that has mass and takes up space

matter

Examples of things that are not matter

light, sound, electricity

There are ____ elements.

114

There are _____ naturally occurring elements.

92

several elements are

synthetic, created by a scientist

what is the most abundant element in the human body?

oxygen

element

a substance that cannot be broken down into a simpler substance

elements are ___________ of matter.

building blocks

Each element is made up of

one kind of atom.

Each element is represented by

a one, two, or three letter symbol that is used worldwide.

atom

the smallest unit of an element that maintains the chemical properties of that element.

atoms join together to form

molecules

molecule

a group of atoms held together by chemical forces

Most molecules are made of

atoms of different elements, but some are made of atoms of the same element.

compound

a substance made up of atoms of two or more different elements joined by chemical bonds in a fixed proportion

example of a compound

water

hydrogen peroxide has

two hydrogen atoms, 2 oxygen atoms

carbon dioxide has

1 carbon atom, 2 oxygen atoms

carbon monoxide

1 carbon atom, 1 oxygen atom

Every compound is ________________ from the elements it contains.

unique and different.

Compounds have

chemical formulas

Chemical formulas

shows how many atoms of each element-a unit of a substance.

number in front of the chemical formula is the number of

molecules

pure substance

any matter that has a fixed composition and definite properties

Pure substances are NOT

mixtures.

Pure substances include

elements and compounds.

examples of pure substances.

water, sugar, salt

mixture

a combination of two or more substances that are not chemically combined and do not have a fixed composition

heterogeneous mixture

components are not evenly distributed and components can be distinguished

homogeneous mixture

components are evenly distributed and appear the same throughout

liquids that are not carbonated can also contain gases. The foam on top is a

gas-liquid mixture.

compounds have a

set proportion of elements by weight, separated by chemical means.

mixtures are separated by

physical means.

suspension

a mixture in which particles of a material are more or less evenly disperse throughout a liquid or a gas

A property of a suspension is that the

particles settle out of the mixture when it is allowed to stand

The particles in most suspensions are about the size of a

bacteria cell.

Suspension particles are large enough to be

filtered out of the mixture.

decanting

the process of pouring a less dense liquid off of a denser liquid

colloid

a mixture consisting of tiny particles that are intermediate in size between those in solutions and those in suspension, and that are suspended in a liquid, gas, or solid

the particles in a colloid are smaller than those in a

suspension

Colloid particles do not

settle out of the mixture. they remain spread throughout.

emulsion

a colloid in which liquids that usually do not mix are spread throughout each other

emulsifier

coats one of the immiscible liquids allowing the immiscible liquids to spread throughout each other

All homogeneous mixtures are

solutions.

solute

the substance that dissolves in the solvent

solvent

the substance in which the solute dissolves.

What is the universal solvent

water

A mixture of liquids can form a

solution

One way to separate miscible liquids is by the process of

distillation

distillation separates

miscible liquids that have different boiling points

A mixtures of gases can form a
example:

solution
air

Alloys

a homogeneous mixture of 2 or more metals

What are three examples of alloys?

bronze, brass, and steel

Amalgam solution

Mercury is dissolved into solid silver.

Many common solutions are solids dissolved in

liquids

Please allow access to your computer’s microphone to use Voice Recording.

Having trouble? Click here for help.

We can’t access your microphone!

Click the icon above to update your browser permissions above and try again

Example:

Reload the page to try again!

Reload

Press Cmd-0 to reset your zoom

Press Ctrl-0 to reset your zoom

It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.

Please upgrade Flash or install Chrome
to use Voice Recording.

For more help, see our troubleshooting page.

Your microphone is muted

For help fixing this issue, see this FAQ.

NEW! Voice Recording

Click the mic to start.

Create Set