CHM 170: Exam 1 Study Guide
37 Cards in this Set
| Front | Back |
|---|---|
|
Chemistry
|
The branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.
|
|
Matter
|
anything that occupies space
|
|
Properties
|
To a chemist, it is a list of physical and chemistry aspects.
|
|
Substances
|
Has a definite (constant) composition and distinct properties
|
|
Chemical
|
A substance with distinct properties that is produced by or used in a chemical process
|
|
atom
|
the basic unit of a chemical element
|
|
molecules
|
two or more atoms attached together in a specific geometrical arrangement.
|
|
Bonds
|
attractive forces that hold atoms together
|
|
Pure substance
|
can not be separated by physical means
|
|
Element
|
cannot be chemically broken down into simpler substances
|
|
compound
|
combination of two or more elements
|
|
Mixture
|
can be separated by physical means
|
|
Homogenous mixture
|
composition of the mixture is uniform throughout
|
|
heterogeneous mixture
|
composition is not uniform throughout
|
|
Solid
|
the form of matter characterized by rigidity; a solid is relatively incompressible and has a fixed shape and volume
|
|
Liquid
|
the form of matter that is relatively incompressible fluid; liquid has a fixed volume but no fixed shape
|
|
gas
|
the form of matter that is an easily compressible fluid; a given quantity of gas will fit into a container of almost any size and shape
|
|
Physical properties
|
can be determined without changing the chemical makeup of the sample.
- melting point, boiling point, density, mass, touch, taste, temperature, size, color, hardness, conductivity
|
|
Chemical properties
|
those that do change the chemical make up of the sample.
- burning, cooking, rusting, color change, souring of milk, ripening of fruit, browning of apples, taking a photograph, digesting food.
|
|
Energy
|
the capacity to do work
|
|
Kinetic energy
|
the energy of motion
-motion of the atoms, molecules, and subatomic particles
-thermal (heat) energy is a form of kinetic energy because it is caused by molecular motion
|
|
Potential energy
|
Energy that is stored in the matter.
-due to the composition of the matter and its position relative to other things
-chemical potential energy arises from electrostatic attractive forces between atoms, molecules, and subatomic particles
|
|
exact number
|
things you can count or defined equalities
|
|
Measured numbers
|
are numbers that come from a device that measures things like height, weight, temperature.
|
|
Prefixes for units
|
-tera, T, 1x1012
-giga, G, 1x109
-mega, M, 1x106
-kilo, k, 1x103
-deci, d, 1x10-1
-centi, c, 1x10-2
-milli, m, 1x10-3
-micro, ü, 1x10-6
-nano, n, 1x10-9
|
|
Precision
|
refers to how close a series of measurements are to one another
|
|
Accuracy
|
refers to how close the measure value is to the actual value
|
|
Scanning Tunneling Microscope (STM)
|
-Developed in 1981
-Allows scientists to image individual atoms
-Also, allows scientists to move individual atoms across the surface
|
|
Modern Atomic Theory
|
The theory that all matter is composed of atoms grew out of observations and laws
|
|
The Law of Conservation of Mass
|
(1774, Antoine Lavoisier)
- In a chemical reaction, matter is neither created nor destroyed
|
|
The Law of Definite Proportions
|
(1797, Joseph Proust)
- All samples of a given compound, regardless of the source or how they were prepared, have the same proportions of their constituent elements.
|
|
The Law of Multiple Proportions
|
(1804, John Dalton)
- When two elements (call them A and B) form two different compounds, the masses of element B that combine with 1 g of element A can be expressed as a ratio of small whole numbers.
|
|
John Dalton and the Atomic Theory
|
- Each element is composed of tiny, indestructible particles called atoms
- All atoms of a given element has the same mass and other properties that distinguish them from atoms of other elements.
- Atoms combine in simple, whole-number ratios to form compounds
- In a chemical reaction,…
|
|
J.J. Thomson Cathode Ray Experiments
|
(1897) cathode ray tube.
- The cathode rays are made of tiny particles
- these particles have a negative charge
- every material tested contained these same particles
- the amount of deflection was related to two factors, the charge and mass of the particles
- the charge/mass of thes…
|
|
Thomson's Conclusions (cont.)
|
-if the particle has the same amount of charge as a hydrogen ion, then it must have a mass almost 2,000x smaller than hydrogen atoms.
-Later experiments by Millikan showed that the particle did have the same amount of charge as the hydrogen ion
-The only way for this to be true is i…
|
|
Rutherford's Gold Foil experiment
|
(1909) He concluded that matter must not be as uniform as it appears. It must contain large regions of empty space dotted with small regions of very dense matter.
|
|
isotopes
|
atoms with the same number of protons but a different number of neutrons
|
CHM 170: Final Exam Study Guide