physical science reference charts - thelearningodyssey.com · physical science reference charts...

© 2012 CompassLearning

Physical Science Reference Charts

Atom

Properties of Particles Smaller Than Atoms

Particle Charge Mass (amu)

Proton +1 1

Neutron 0 1

Electron -1 ~1/1823


Key to the Periodic Table:

Green – metals

Purple – metalloids

Orange – nonmetals

Orange rightmost column – noble gases


States of Matter Molecules in a solid cannot move around. They vibrate in place.

Molecules in a liquid collide and can move past each other, as well as vibrate.

Molecules in a gas can collide and move about freely, as well as vibrate.

Plasmas:

no fixed volume

no fixed shape

freely moving particles


Chemical Changes and Reactions A chemical change (reaction) creates new substances (while a physical change affects the shape or form of the substance). Even though new substances are formed in a chemical reaction, the overall types and numbers of atoms stay the same. Reactants: atoms, molecules, or compounds present at the start of a chemical reaction that participate in the reaction. Products: atoms, molecules, or compounds formed in the reaction. Synthesis reaction: when two substances combine to form a third substance (e.g., 2Na + Cl2 → 2NaCl). Decomposition reaction: when a single compound reacts to produce two or more substances (e.g., CaCO3 → CaO + CO2). Combustion reaction: when a substance reacts with oxygen, usually with a sudden release of heat, to create a flame (e.g., 4Fe + 3O2 → 2Fe2O3). Displacement reaction: when one element reacts with a compound, displacing a different element from it (e.g., Zn + 2HCl → ZnCl2 + H2).

Balancing Chemical Equations In order for a chemical equation to reflect the law of conservation of matter, it must be balanced. Balanced chemical equation: the numbers and types of atoms shown on the reactants side match the numbers and types of atoms shown on the products side. Chemical equations are balanced by adjusting the coefficients. Coefficients: numbers before chemical formulas indicating the number of copies of a substance. Unbalanced equation: Na + Cl2 → NaCl Balanced equation: 2Na + Cl2 → 2NaCl


Chemical Reactions and Heat Exothermic reaction: a chemical reaction in which heat or light energy is given off. Examples:

combustion

cellular respiration

C6H12O6 + 6O2 → 6CO2 + 6H2O + energy

The heat or light energy released in an exothermic reaction was stored in chemical bonds as chemical energy. Endothermic reaction: a chemical reaction in which heat or light energy is taken in during the reaction and stored in chemical bonds. Examples:

photosynthesis 6CO2 + 6H2O + energy → C6H12O6 + 6O2

reactions in an egg as it is cooked


Formula for average speed:

ds

t

s: average speed d: distance traveled t: time taken

Triangle Trick: can be used to find equations for calculating distance, speed, and time. Cover the variable you want to solve for.

Net Force

Net force: the sum of all the forces acting on an object.

A force (a push or a pull) has both a magnitude (size or strength) and a direction. newton [N]: the standard unit of force in the metric system. A medium-sized apple weighs about one newton. Weight: the gravitational force acting on an object. Net force example: If a box sits on a table and an upward pulling force on the box is greater than the weight of the box, the box will be raised above the table. The frictional force always points opposite to the direction an object moves, or tries to move. If an applied force is greater than the frictional force acting on an object, the object will move in the direction of the applied force. When the forces acting on an object are balanced, the net force is zero (Fnet = 0).

When the forces acting on an object are balanced, they are equal in strength but

opposite in direction.

Unbalanced forces happen any time an object changes its speed or direction.


Steps to Solve for Force, Mass, or Acceleration Step 1: Identify Information in Problem Step 2: Identify Formula to Use

Know Need Formula

Two of these: F (force) m (mass) a (acceleration)

F, m, or a F = m × a Rewrite using algebra or the triangle trick, if needed.

Step 3: Plug in Numbers and Solve

Double-check that your numbers and units are both correct.


Newton’s Laws of Motion

Newton’s laws of motion describe how objects move (and why sometimes they

don’t).

Newton’s first law of motion:

Objects remain at rest or in motion at a constant velocity unless acted on by an

unbalanced force.

Newton’s second law of motion:

Force = mass × acceleration

F = m × a

Unbalanced forces accelerate masses.

Acceleration: a change in speed and/or direction; measured in m/s/s (or m/s2).

Newton’s third law of motion: “Action-reaction law”

For every action force, there is an equal (in magnitude) and opposite (in direction)

reaction force.

Newton’s third law of motion does not require that there be something to push off

against!

Volume Formula for volume of a rectangular solid:

V = L × W × H

V: volume L: length W: width H: height


The volume of a solid object of any shape can be determined by measuring the

amount of fluid that it displaces.

Density

Formula for density:

mD

V

D: density m: mass V: volume

Triangle trick: can be used to find equations for calculating mass, volume, and density. Cover the variable you want to solve for.


Buoyant Force When the weight is greater than the buoyant force, an object sinks.

When the weight and the buoyant force are equal, an object floats.

Potential and Kinetic Energy Potential energy: stored energy in an object. Some types of potential energy:

elastic

gravitational

chemical Kinetic energy: energy in the form of moving matter. Kinetic energy depends on the mass and the speed of a moving object.


Simple machines

Formulas for simple machines:

Mechanical advantage = output force

input force

Mechanical advantage of inclined plane = length of plane

height of plane

Mechanical advantage of pulley system = number of rope segments supporting the load

Percent efficiency = energy produced by machine

100%energy put into machine

Percent efficiency = work output

100%work input


Atoms have heat energy as a result of their motion.

The faster the atoms are vibrating, the more heat energy each atom has.

The atoms in a hot mug are vibrating faster than the atoms in an ice cube.

Temperature: a measurement of the average kinetic energy of the particles in a

substance.

Conduction: the transfer of heat by direct contact.

Conduction heat transferred between particles next to one another

Convection: a looping pattern of heat flow due to the motion of particles.


Radiation: the transfer of heat by light waves.

Wave: a traveling disturbance.

There are two main kinds of waves:

1. Mechanical waves need matter in order to travel.

2. Electromagnetic waves do not need matter to travel.

Examples of waves include:

water waves [mechanical]

seismic waves [mechanical]

sound waves [mechanical]

light waves [electromagnetic]


Characteristics of waves:

Frequency: the number of waves that pass by a point in a certain amount of time.

Frequency and wavelength are connected to one another.

shorter wavelength higher frequency

longer wavelength lower frequency


Transverse wave: a wave in which the direction the medium moves is perpendicular to the direction in which the wave travels

Longitudinal wave: a wave in which the direction the medium moves is parallel to the direction in which the wave travels


Transmission: allowing light to pass through.

Example of transmission: visible light shining through a window

Absorption: taking in energy and storing it (especially light).

Example of absorption: a black shirt absorbing sunlight, making you hot

Scattering: light bouncing off an object in many different directions.


Example of scattering: reflection from a mirror

Law of reflection: the angle of incidence equals the angle of reflection.


Light travels at different speeds, depending on the substance it is traveling in:

Substance Speed of Light

(kilometers per

second)

Air 300,000

Water 225,000

Glass 200,000

Diamond 120,000

When light enters a medium in which it slows, it will be bent toward a line drawn

perpendicular to the point of refraction.

When light enters a medium in which it speeds up, it will be bent away from a line

drawn perpendicular to the point of refraction.


Light from a source comes directly to our eyes, allowing us to see the source.

We can see objects that do not produce their own light when they reflect light

from a light source.


Lens: an object that bends the light passing through it to create an image.

physical science reference charts - thelearningodyssey.com · physical science reference charts...

Documents