Ev Sci Ch 2

Matter - anything that has mass and takes up space.

Solid, liquid, gas

Can be an element or a compound

Element - a type of matter with a unique set of properties that cannot be broken down into simpler substances by chemical means.

Compound -  combinations of two or more different elements held together in fixed proportions

Atom = basic building block of matter

Smallest unit of matter into which an element can be divided and still have distinct chemical properties

Can be further broken down into protons and neutrons and electrons.

Proton - positive charge

Neutron - no charge

Electron - negative charge

Atoms can have different mass numbers (varying numbers of nuetrons), creates isotopes

Isotope - Same atomic number, different mass number

Most common isotopes of carbon are carbon-12, carbon-13, carbon-14

Molecule - Second building block of matter

Combination of two or more atoms of same or different elements held together by forces known as chemical bonds

Organic compound - carbon-based compound.

Organic compounds get very complex.

Include simple carbohydrates that contain C, H, O atoms.

More complex compounds are polymers

Polymers consist of multiple monomers.

Glucose is a simple carbohydrate which is a monomer for complex carbohydrates such as starch and cellulose.

Other types of polymers are proteins, nucleic acids, and lipids.

Proteins are made of amino acids

Nucleic acids are made of nucleotides

Lipids are made of fats

Physical change - no change in chemical composition

Paper being ripped in half

H2O melting and freezing

Chemical change - change in chemical composition.

Use a chemical equation to show how chemicals are rearranged.

Matter is never created nor destroyed

Matter is only rearranged into different forms

Energy - Capacity to do work

Two types of energy

Potential and kinetic

Kinetic energy - energy associated with movement.

Flowing water, speeding car,

Thermal energy is a form of kinetic energy

Energy associated with heat

Heat - Movement of energy

Temperature - measure of average heat or thermal energy of the atoms, ions, or molecules

Heat always flows from hot to cold.

Electromagnetic radiation - Changes in electrical and magnetic fields

Electromagnetic radiation from the sun is the major source of energy on the earth.

Potential energy - stored energy, energy associated with position

Potential energy can change into kinetic energy.

Energy Quality - capacity of energy to do useful work

High quality - energy that can do useful work

High temperature thermal energy, high speed wind, energy released by wood, gasoline, natural gas, coal

Low quality - little capacity to do useful work

Majority of moving molecules in atmosphere or in the ocean are low quality.

First law of thermodynamics - law of conservation of energy

Second law of thermodynamics - The universe is always proceeding towards a higher state of entropy

Energy always moves towards a less useful form

System - set of components that function and interact in some regular way

Cells, human body, forest, river

All systems have inputs, throughputs, and outputs of matter

Affected by feedback

Matter, energy, or information that, when fed back into the system as input, increases or decreases a change to the system.

Feedback loop - when an output of matter, energy, or information is fed back into the system as an input and leads to changes in that system.

Causes a system to change further in the same direction

“Snowball effect”

When a natural system becomes locked into a positive feedback loop, it can reach an ecological tipping point

Beyond this point, system can change so drastically it could collapse

Causes system to change in opposite direction

Thermostat

Temperature in house increases until it reaches a set temperature, then furnace is shut off.