Science 2nd Trimester Exam Flashcard

Matter
Anything that has mass and takes up space
Chemistry
The study of matter and how it changes.
Substance
A single kind of matter that is pure; it always has a specific makeup or composition.
Physical Property
A characteristic of a substance that can be observed without changing it into another substance.
Chemical Property
A characteristic of a substance that describes its ability to change into different substances.
Element
A substance that cannot be broken down into any other substances by chemical or physical means.
Atom
The basic particle from which all elements are made.
Chemical Bond
A force of attraction between two atoms.
Molecule
A group of two or more atoms held together by chemical bonds.
Compound
A substance made of two or more elements that are chemically combined in a set ratio.
Chemical Formula
Shows the elements in a compound and the ratio of atoms.
Mixture
Made of two or more substances that are together in the same place, but their atoms are not chemically bonded.
Weight
The measure of the force of gravity on you.
Mass
The amount of matter an object has.
International System of Units
Used to measure the properties of matter. The SI unit of mass is the kilogram.
Volume
The amount of space that matter occupies. The SI unit of volume is the cubic meter.
Volume = Length x Width x Height
Density
The measure of the mass of a material in a given volume. Can be expressed as the number of grams in one cubic centimeter.
Density = Mass/Volume
Physical change
Alters the form or appearance of matter but does not turn any substance in the matter into a different substance.
Chemical Change
A change in matter that produces one or more new substances.
Law of conservation of mass
The fact that matter is not created or destroyed in any chemical or physical change. Also called the law of conservation of matter.
Temperature
The measure of how hot or cold something is.
Thermal Energy
The total energy of the motion of all the particles in an object.
Endothermic Change
A change in which energy is absorbed.
Exothermic Change
A change in which energy is released or given off.
Chemical Energy
The energy stored in the chemical bonds between atoms.
work
Any time you exert a force on an object that causes the object to move some distance.
Work = Force X Distance
joule
The SI unit of work named in honor of Prescott Joule.
Power
The rate at which work is done.
Power = Work/Time
Watt
The SI unit of Power.
Machine
Devices that allow you to work in an easier way. They DO NOT reduce the amount of work you do.
Input Force
The force you exert when you do work.
Output Force
The force exerted on an object by a machine.
Mechanical Advantage
The number of times a machine increases a force exerted on it.
Mechanical Advantage = Output force/Input force
Efficiency
The percentage of input work that is converted to output work.
Efficiency = Output Work/Input Work X 100%
Simple Machine
The most basic device for making work easier.
Inclined Plane
A ramp; a flat, sloped surface.
Wedge
A device that is thick at one end and tapers to a thin edge at the other end.
Screw
An inclined plane wrapped around a cylinder to form a spiral.
Lever
A rigid bar that is free to pivot or rotate on a fixed point.
Fulcrum
The fixed point that a lever pivots around.
Pulley
A simple machine made of a grooved wheel with a rope or cable wrapped around it.
Wheel and Axle
A simple machine made of two connected objects that rotate about a common axis. The object with the larger radius is the wheel.
Compound Machine
A machine that combines two or more simple machines.
Energy
The ability to do work or cause change.
Kinetic Energy
The energy an object has due to motion.
Kinetic energy = 1/2 x Mass x Speed2
Potential Energy
Energy that results from the position or shape of an object.
Gravitational Potential Energy
Potential energy related to an objects height.
Gravitiational Potential Energy = Weight X Height
Elastic Potential Energy
Potential energy related to the shape of an object.
Mechanical Energy
The form of energy associated with the motion, position, or shape of an object.
Nuclear Energy
The potential energy stored in the nucleus of an atom.
Thermal Energy
The total kinetic and potential energy of the particles in an object.
Electrical Energy
The energy of electric charges.
Electromagnetic Energy
The energy of light and other forms of radiation that travels through space in waves.
Chemical Energy
The potential energy stored in chemical bonds.
Energy Transformation
A change of one form of energy to another.
Law of conservation of energy
States that when one form of energy is transformed into another, no energy is lost in the process.

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