particles that constitute the fundamental building blocks of ordinary matter.
or more atoms joined in a specific geometrical arrangement.
on OBSERVATION and EXPERIMENT.
interpretation or explanation of the observations.
Highly controlled procedures designed to generate observations that can confirm or refute the hypothesis.
A brief statement that summarizes past observations and predicts future ones.
Not actually a law but rather describes how nature behaves – they are generalizations about what nature does.
Also known as Principles rather then laws
Law of Conservation of mass
In a chemical reaction, matter is neither created nor destroyed.
Scientific theory is a model for the way nature is and tries to explain not merely what nature does but why.
Theories explains our laws
Proposed by English chemist John Dalton (1766-1844)
Explained law of conservation of mass by proposing that matter was composed of small, indestructible particles called atoms.
Summarizes a series of related observations
Theory gives the underlyign reasons for them
Anything that occupies space and has mass. Classify matter according to its state - solid liquid or gas according to its composition
Atom composition in solid matter
Atoms are packed close to each other in fixed locations.
They vibrate against each other but do not move around or past each other
Fixed volume and rigid shape.
what type of mass is a crystalline?
Solid matter may be crystalline. Atoms or molecules are arranged in patterns with long-range, repeating order. The opposite of crystaalline is amorphous.
What kind of matter can be amorphous?
Atoms or molecules do not have long range order. Random order. Such as in Charcoal. The opposite of amorphous is crystalline.
Atoms or molecules pack about as closely as they do in solid matter, but they are free to move relative to each other, giving liquids a fized colume but not a fixed shape.
Lots of space between them and are free to move relative to one another, making gases "compressible". Gases always assume the shape AND colume of their container. HOWEVER Mass of gases always remains the same
Classifications of Matter
A. 1. 2. B. 1. 2.
A. Pure Substanes (not a varying composition) 1. Element (not separable) 2. Compound (separable) B. Mixture (carying composition) 1. Heterogeneous (not Uniform) 2. Homogeneous (uniform throughout)
Composed of only a single type of atom or molecule
Substance composed of two or more differnt types of atoms or molecules that can be combined in variable proportions. A new sample may be differnt from the last.
Substane that cannot be chemically broken down into simpler substances. No single molecule based substance
A substance compsed of two or more elemts in fixed, definite proportions. Such as Water. One molecle or element with no other.
Composition caries from one region to another. One sample is different from another.
Same composition throughout
Separation of a mixture of a solid and a liquid by pouring carefully into another container (usually with a filter to stop the solid but still let the liquid go through)
Boiling off the more colatile part of the mixture to reduce the other part to its pure state. The colatile liquid is then recondensed in a condenser and collected in a separate flask
Change in appearance OR STATE (solid to liquid to gas) but NOT coposition are physical changes.
Atoms rearrange, transforming the origianl substances into different substances. Rust occurs when oxygen combines with iron to form iron oxide - the orange substance we call rust.
One that a substance displays without changing its composition
Smell of gasoline
order taste color appearance melting point boiling point and density
A substance displays only by changing its composition via a chemical change
flammability of gasoine
Corrosiveness flammability acidity toxicity, etc.
Capacity to do work
Defined as the action of a force through a distance
Energy associated with its motion.
The potential energy of a ball on top of a hill is transferred to kinetic energy when the ball is let go.
this moving energy is let go of with heat. So the potential energy will be greatest and the kinetic energy will eventually slow, the potential energy will also slow due to its position
Coverted to thermal energy
Essentially trasferred to the atoms and molecules that compose the ground, raising the temperature of the ground ever so slightly.
Eneryg associated with its position or composition
the ability to produce motion in motivation by gravity
Energy associated with the temperature of an object
The heat given off by movement of its molecules/atoms.
High Potential Energy
Once the potential energy is released, the energy (noow thermal) is stable (less likely to cause movement)
Metric Length Unit
1 meter - slightly longer then a yard
1 meter (39.37 in ) = 1 yard (36in)
Measure of MASS (quantity of matter within it) not weight
One kg - 2.205 lb
Metric Time Unit
Celsius Water freezes at 0 and boils at 100
Kelvinsystem 0 is absolute coldest possible temp. (-273 C and -459 F)
Amount of substance
Combination of other units
m/s meters per second
Measure of space - cubic meter m^3 cubic centimeter
Density of a substance is the ratio of its mass to its colume
D - mass/volume of D =m/v
Density of aluminum, for example, will always remainthe same no matter the quantity - unless work is involved. (heat etc)
One that is independent of the amount of the substance
One the depends on the amount of the substance
Refers to how close the measured calue is to the actual value
Refers to how close a series of measuements are to one another of how reproducible they are.
Error that has equal probability of being too high or too low.
Using units as guide to solving problems.
A fractional quantity with the units we are converting from on the bottom and the units we are converting to on the top.