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What is chemistry?
the study of matter and the changes it undergoes.
what are some fields of chemistry use?
- medicine: doctors, nurses, pharmacies
- cleaning supplies etc.
Where do chemists work?
they can work in a lab, a research environment, or giving advice on chemistry for projects.
Why should we study chemistry?
- Because it is important to understand the world around us.
- It can explain cooking, cleaning, medicine and environmental issues.
If you know chemistry, you can make educated choices about the products you use.
what can chemistry explain? (5 things)
cooking, cleaning, environmental issues and agriculture (fertilizers, pesticides etc)
What is fertilizer?
What three elements make it up?
It helps make plants grow.
What is the difference between regular fertilizers and organic fertilizers?
REGULAR fertilizers: made by mixing chemicals
ORGANIC fertilizers: made by mixing natural ingredients like chicken poo, blood and bone meal.
What is pesticide?
Name 4 types of pesticide!
A pesticide is a substance or mixture of substances used to destroy any pest.
- BACTERICIDES: destroy, supress or prevent BACTERIA
- BAITS: Products that need to be mixed with food to control a pest.
- FUNGICIDE: control or destroy the effect of a fungus
- HERBICIDE: controls weeds and unwanted vegetation
What is a pure substance?
A substance with a definite and constant composition.
can be an ELEMENT or a COMPOUND, but the composition doesn't vary.
Examples: sugar, salt, gold
What is an element?
Composed of a single kind of atom
Example, GOLD, HYDROGEN
What is a COMPOUND?
it is composed of two or more elements.
example: water, sugar
What is a mixture?
it displays properties of the contents and do not have their own characteristic properties
a combination of elements and compounds.
example is sugar water
WHAT is a HOMOGENEOUS mixture?
It is formed by the combination of a SOLUTE in a SOLVENT.
It cannot be separated by the eye or through a microscope.
It is uniformly mixed and cannot be seperated by physical separation.
can also be called a SOLUTION.
examples: chocolate milk, coffee, sugar water.
What is a HETEROGENEOUS mixture?
a mixture where the SOLUTE and the SOLVENT are seen and can be separated.
A non-uniform mixture in which the components are separate.
EX: spaghetti and spaghetti sauce, rice and beans
What is a solid
the molecules are very close together and cannot be moved.
Fixed shape and definite volume
examples: rocks, wood
What is a liquid?
molecules are close together and move slowly.
Fixed volume but not fixed shape
What is GAS?
Molecules are widely separated.
Volume is not fixed nor is the shape
examples, steam, helium
What is plasma?
A gas composed of free-floating ions and free electrons.
It conducts electrical currents.
NO fixed volume or shape
What is the periodic table
It is a table of the chemical elements in which the elements are arranged by order of atomic number and periodic properties
It includes molecular weight or mass
What are the GROUPS in the periodic table>?
the GROUPS are vertical
The groups have similar PROPERTIES
What are the PERIODS in the periodic table?
they are HORIZONTAL
Where are ALKALI METALS?
In reactions, they lose a single electron
What are ALKALINE EARTH METALS, where on the table and charactistics?
These elements lose two electrons.
What are HALOGENS, where on the periodic table and what are their characteristics?
They gain a single electron in reactions.
What are noble gases, where on periodic table and characteristics?
They are very unreactive.
What is an ION?
An atom or molecule in which the total number of electrons is not equal to the total number of protons, giving the atom a POSITIVE ELECTRICAL charge.
What is a CATION?
A neutral atom loses one or more electrons, it has a net positive charge.
WHAT is an ANION?
If an atom gains electrons, it has a net negative charge.