Download An Introduction to Mixtures and Solutions

An Introduction to Mixtures
and Solutions
Sixth Grade Science
Kit #2
Goals for this unit
 Gain experience with the concepts of mixture,
solution, concentration, saturation, chemical reaction.
 Apply an operation definition to determine the
relative concentrations of solutions.
 Acquire vocabulary associated with chemistry and the
periodic table.
 Be introduced to the concept that all matter is made
of very small particles called atoms and that atoms
combine to form molecules.
Background Information:
The Basis Of It All
 Everything in the universe can be put into one of two
categories: matter or energy
 Matter – is the material of the universe
 Energy – is the drive that makes things happen
 Chemistry – is the study of the properties,
relationships, and the interactions of matter and the
energy changes that result from chemical
interactions.
What is matter made of?
 Matter is made up from the 92 naturally occurring
chemical elements.
 Some are familiar substances: sulfur, silver, hydrogen,
and iron.
 Some are rare substances: erbium, gadolinium,
lutetium, and rhenium.
What are the elements made of?
 The elements themselves are made up of atoms,
which are the smallest particles into which an
element can be divided yet retain all of its
characteristics.
Background facts…
 It is thought that the Earth’s core consists of nickel,
iron, and other heavy metals.
 The Earth’s crust makes up 98% of the minerals:
oxygen, silicon, aluminum, iron, calcium, sodium,
potassium, and magnesium.
 There is hydrogen in the water on earth.
 By mass, about 75% of the Earth’s crust (land, oceans,
and atmosphere) consists of oxygen and silicon.
Background facts…
 11 elements are common in living organisms, with
hydrogen and oxygen the most abundant.
 In the human body, 97% of the atoms are nitrogen,
oxygen, carbon or hydrogen.
 The rest of those 11 elements include: sulfur,
phosphorus, calcium, sodium, potassium, magnesium,
and chlorine.
Background facts…
 Atoms are not usually found in pure (elementary)
from, but are attached to other atoms in stable
associations of molecules.
 A molecule that contains atoms of more than one
element is called a compound.
 Compounds can be simple, composed of two or three
atom units, like water, salt and carbon dioxide or they
can be complex, like hemoglobin and chlorophyll.
Water molecule
Carbon Dioxide Molecule
Chlorophyll Molecule
Hemoglobin Molecule
Background facts…
 On our planet, matter appears in only three states—
solids, liquids, and gas.
 Examples:
 Solid – A piece of gold
 Liquids – Water
 Gas -- Oxygen
Background facts…
 Changes in state:
 Often when a solid is heated, it melts and becomes a
liquid. If heating continues, the liquid might vaporize
and become a gas. When water loses enough heat, it
turns to a solid called ice. When water collects more
heat, it evaporates and turns into a gas called water
vapor.
Putting different kinds
of matter together
 Mixture – When two or more kinds of matter are
combined.
 Simple mixtures include: sand and water, oil and
vinegar, nuts and bolts, coleslaw, and rocky-road ice
cream.
 Mixtures can be made with any combination of gases,
liquids, and solids.
Can mixtures be separated once
they’re together?
 Yes. Mixtures can be separated using mechanical
means, such as hand separation, screening, and
filtering. The components of a mixture are not
changed by mixing with other materials.
Other terms to know…
 Dissolving – when a solid disappears in a liquid (like
salt in water)
 Solution – The liquid that is left after a solid was
dissolved in it.
 Solvent and Solute – When a solid dissolves in a liquid,
the liquid is the solvent and the solid material is the
solute.
 Evaporation – When the liquid changes to a gas, the
gas moves into the air, and the solid is left behind.
Safety First
 Because of the materials we will be working with, you
must abide by the following rules.
 Never put anything in your mouth. Do not taste anything.
 Do not smell any unknown materials.
 Avoid touching your face, mouth, ears, or eyes while working
with the chemicals.
 Do not mix unknown chemicals just to see what might
happen.
 Always wash your hands immediately after using chemicals.
Safety First





Clean up spills immediately.
Clean up your work space after each investigation.
Be careful when using sharp or pointed tools.
Report all accidents, even small ones, to your teacher.
Follow directions and ask questions if you’re unsure of
what to do.
 Behave responsibly during the science investigations.
 IF YOU DO NOT FOLLOW THESE RULES, YOU WILL
NOT BE PERMITTED TO PARTICIPATE IN THE LABS.