science exam

atmosphere

The layer of gas surrounding earth, mostly nitrogen(78%) and most of the rest is oxygen(21%)

Lithosphere

Earth's solid outer layer

hydrosphere

all of earths water in gas liquid or solid form

Biosphere

where you find living things on earth

population

a group of individuals of the same species living together

community

different populations living together in the same area

Eycosystem

when you include abiotic components to a community if becomes an ecosystem

biotic

living things examples include butterflies, bacteria and plants

abiotic

Non-living things which include rocks, temp and sunlight

Photosynthesis

CO2 + H2O + light energy → C6H12O6 + O
light energy + carbon dioxide + water → glucose (sugar) + oxygen
Plants (producers) capture the Sun's energy and turn it into chemical energy
A pigment called chlorophyll (found in chloroplast) captures light energy and converts it

cellular respiration

C6H12O6 + O2 → CO2 + H2O + energy
glucose (sugar) + oxygen → light energy + carbon dioxide + water
Stored energy in sugars is released by cells to do all their activities.
All organisms do cellular respiration in order to use the sun's energy including plants
This process occurs continuously - as chemical energy is used- it must be replaced

Producers

make their own energy (glucose) using the sun

consumers

must eat to obtain energy

Decomposer

get their energy by eating the remains of dead or decaying plants and animals

Herbivore

organisms that only eat producers for energy
Known as primary consumers

Carnivore

organisms that only eat other consumers for energy
Known as secondary and tertiary consumers

Omnivores

organisms that eat both producers and other consumers for energy
Known as secondary consumers

Scavengers

animal that feeds on the remains of other organisms

Habitat

Where the species live.

Niche

The role of a species within an ecosystem. Includes what it feeds on, what eats it, and how it behaves.

10% rule

After Each organism uses approximately 90% of the energy it takes in for bodily processes, so only 10% get stored and is passed to the next trophic level. This makes a pyramid pattern of energy through food chains.

Pyramid of Numbers

Shows the number of organisms at each trophic level

Pyramid of Biomass

Shows the dry biomass of a population at each trophic level

Pyramid of Energy

Shows the amount of energy passed on to the next trophic level

Nutrient

The source of building materials and chemical energy for cells. All living things need nutrients and you get them from food, water and air.

Nutrient cycle

A biochemical cycle where chemicals that produce nutrients are consumed, rearranged, stored, and used.

Carbon sinks

Carbon-rich deposits (stored carbon) that can be accessed over relatively short times. Fossil fuels are the most valuable carbon deposits.

Carbon cycle

the biochemical cycle where carbon is cycled through the lithosphere, atmosphere, hydrosphere, and biosphere.

Carbon cycle

the biochemical cycle where carbon is cycled through the lithosphere, atmosphere, hydrosphere, and biosphere.

nitrogren cycle

Bacteria

Bacteria plays an important role in the nitrogen cycle because it converts the nitrogen into different forms.

Nitrogen-fixing bacteria

nitrogen gas is converted into ammonia(NH3) or ammonium(NH4+) through
ammonification.

Nitrifying bacteria

ammonia and ammonium are converted into nitrates(NO3-) and nitrites(NO2-) through nitrification.

Denitfification bacteria

nitrates are converted back into nitrogen gas through denitrification.

Matter

Anything that takes up space and has mass

Physical properties

Describes the physical traits of the substance itself, qualitative and quantitative properties, doesnt change chemical identity
Examples:Color, Length, Volume, Opacity

Chemical properties

Describes how a substance reacts with other substances

Qualitative

A characteristic of matter that can be observed and described using the 5 senses

Quantitative

A characteristic that is measured it involves numbers and units

Physical change

occurs when no new substances are formed

Chemical change

is when two or more new substances are formed

Evidence of chemical change:

Formation of precipitate (a solid that forms during a chemical reaction)
Formation of bubbles (water boiling is an exception)
Change in colour
Change in temperature
Change in odour

STAMP

All matter is made up of tiny particles that have empty spaces between them.
Different substances are made up of different kinds of particles
Particles are in constant random motion
The particles of a substance move faster as temperature increases
Particles attract each other.

Pure substance

A type of matter that consists of only one type of particle (elements and compounds)

Mixture

A type of matter that contains more than one type of particle (solutions and mechanical mixtures)

Mechanical mixture/heterogenous

a mixture where you can tell apart the different substances in it. Liquids and gas mech mixtures will be opaque/murky.
Ex. milk, cereal, fog.

Solution/homogenous mixture

a mixture where you can't tell apart the different substances.
Ex. apple juice and blood.

Element

A pure substance that cannot be broken down into a simple chemical substance

Compound

A pure substance of two or more elements chemically combined.

Atoms

Atoms make up elements

Molecules

A type of compound

Diatomic elements

appear in pairs
Hydrogen,Oxygen,Fluorine,Bromine,Iodine,Nitrogen,Chlorine.

Metal

A lustrous, malleable, and ductile element that conducts heat and electricity.

Non-metal

Usually gas or dull powdery solid element that does not conduct heat or electricity.

Mettaloid

Has properties of both metals and non-metals

periodic table

Groups

vertical columns on periodic table, represents valance electrons

Periods

horizontal rows on periodic table, represents shells

Alkali metals (group 1)

shiny soft, highly reactive, low density.

Alkaline earth metals (2)

shiny, harder, and less reactive than alkali metals

Halogens (17)

very reactive, poisonous

Noble gases (18)

all gases, not reactive, glow when energized

Democritus

First to say that matter is made of particles to create atoms

John Dalton

"The Billiards Model"

JJ Thomson

"The Plum Pudding Model"

Ernest Rutherford

"The Bohr-Rutherford Model"

James Chadwick

"The Planetary Model"

Niels Bohr

"The Bohr-Rutherford model"

Bohr-Rutherford Model

Combines Bohr and Rutherford's contributions
Model shows number of protons and neutrons in the nucleus
Shows arrangement of electrons in different orbits around the nucleus

\# of neutrons \= average atomic mass - \# of protons

Isotope

atom with the same number of protons but a different number of neutrons
Average atomic mass of an isotope is different than a neutral atom because average atomic
mass is protons plus neutrons.

Valance electrons

group 1(Alkali meta) \= 1VE, group 18(Noble gas) \= 8VE(full outer shell)

Ions

Atomes that have gained or lost electrons
Become more stable bc it changes to have a full outer shell/become a noble gas

Anions

form when electrons gain electrons to have a full outer shell
You add electrons so it will have a negative charge
Tend to be nonmetals

Cations

form when atoms lose electrons, positive charge
Tend to be metals, except hydrogen

Ionic compounds

The attraction of a cation and an anion is an ionic bond that forms an ionic compound
The elements in ionic compounds are ions
The cations are bonded to the anions

Bonds

Metal atoms give electrons and non-metal atoms receive electrons in order to end up with a complete outer shell
Cations - give electrons
Anions - receive electrons

Formula

A ratio of cations to anions
The cation is written first

Example

Calcuim has a positive charge of 2 and fluorine has a negative charge of 1
You would swap the numbers (not charges) and write the symbol out with the new number on the bottom
Add ide at the end of the second word
Ca+2 F-1 \=CaF2
Calcium fluoride

Molecular compounds

Non-matals bonding together, known as covalent bonds
Share electrons
From common stubsances
NH3

Covelent bonds

Atoms in a molecular compound are held together by covalent bonds
Atoms with unparied electrons form covenant bonds to have a full outer shell

Lewis symbols

can be used to find ionic compound formulas
Plot the number of electrons on the outer shell on the element symbol

The electrostatic series

a list of materials arranged in order of likelihood to gain electrons
As you move further down the list, the tendency to gain electrons increases

Insulators

substances with electrons that cannot move easily
Can be charged if electrons are gained or lost
They slow down the flow of electrons or passage of current through them
So we use them extensively in circuit boards and high-voltage systems
Examples:
Plastic
Wool
Glass
Drywood

Conductors

substances with electrons that can move easily
Can be charged if electrons are gained or lost
​Our cooking utensils like kettles, irons, boilers, etc., are made of conductive materials.
Examples:
Metals like copper and iron
Water with ions like tap water and pools

Law of electrical charges

Like obects repel
Unlike objects attract

Neutral objects

they are attracted to charged objects
Charged objects cause electons to move into the netural obeject a temporary creating a temporary charge separation
The charge separation produces opposite charges which attract

Friction

Charging by friction is when electrons are transferred between two neutral objects when they are rubbed together
Some substances tend to give electrons while others take them
This leaves one object with a positive charge and the other with a negative charge

Example for friction

What is a charge on an acetate sheet if rubbed on cotton? (refer back to electrostatic series)
When rubbed, the acetate will become positive. The cotton has a higher tendency to gain electrons, meaning the acetate will give away electrons.

charging with friction

neutral object is touched by a charged object.
Negative charge

the electrons from the charged object move into the neutral object. Neutral object gets a permanent negative charge when the objects are separated.

neutral object is touched by a charged object.
postive charge

the electrons from the neutral object move into the charged object. Neutral object gets a permanent negative charge when the objects are separated.
Both the rod and neutral object end up with the same charge.

electroscope

The leaves repel when there is a charge. It cant tell u if the charge is positive or negative.

Electrical discharge

when they electrical charge is removed from an object and not "trapped" anymore.

Lightning is electrical discharge caused by induction

there is friction in clouds from densely packed particles and the charge builds up at the bottom and repels electrons in earth's surface. When there is enough difference between the earth and clouds electrons are sent to the earth through lightning to neutralize everything.

Grounding

Connecting an object to the earth (the ground) effectively removes the charge(positive or negative) from the object.

Current electricity

the controlled flow of electrons through a conductor

Electric circuits

require a flow of electrons on a continuous path
Load - converts electrical energy into other forms of energy
Energy source - allows for electrical energy?
Switch - controls the flow of electrons by opening or closing the circuit
Electrical wires - pathway for electrons to flow

Short circuit

A circuit with no load.
Hazards - Fire, electrocution, electric shock.

Positive terminal

found on the side that has the longest line of the battery (usually right)