CHE2A Chapter 1
Terms
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- Significant Figures Rules
- (1) All nonzero digits are significant (2) Zeros are also significant, but with two important exceptions for quantities less than one. Any zeros 1) preceding the decimal point, or 2) following the decimal point and preceding the first nonzero digit are not significant (3) The case of terminal zeros that precede the decimal point in quantities greater than one is ambiguous
- Fahrenheit from Celsius
- t (°F) = (9/5) t (°C) + 32
- Intensive Property
- is independent of the amount of matter observed
- Element
- the different type of atoms
- Properties
- are those qualities or attributes that we can use to distinguish one sample of matter from others
- Induction
- the form of reasoning in which a general statement or natural law is inferred from a set of observations
- Homogeneous Mixture or Solution
- a mixture that is uniform in composition and properties throughout
- Distillation
- when a pure liquid is condensed from the vapor given off by a boiling solution
- Significant Figures
- gives an indication of the capabilities of th measuring device and the precision of the measurements
- Matter
- is anything that occupies space and displays the properties of mass and inertia
- Accuracy
- refers to how close a measured value is to the accepted, or actual, value
- Liquid
- the atoms or molecules are usually separated by somewhat greater distances than in a solid
- Heterogeneous Mixture
- the components separate into distinct regions
- Mass
- describes the quantity of matter in an object
- Microscopic Level
- describes matter as chemists conceive of it-in terms of atoms and molecules and their behavior
- Chemical Change or Chemical Reaction
- one or more kinds of matter are converted to new kinds of matter with different compositions
- Significant Figures in A & S
- the result must be expressed with the same number of digits beyond the decimal point as the quantity carrying the smallest number of digits
- Celsius from Fahrenheit
- t (°C) = (5/9) [t(°F) - 32]
- Scientific Method
- is the combination of observation, experimentation, and the formulation of laws, hypotheses, and theories
- Physical Change
- when a physical property of a sample changes
- Fahrenheit Scale
- the melting point of ice is 32°F, the boiling point of water is 212°F, and the interval between is divided into 180 equal parts
- Derived Units
- measured properties that are expressed as a combination of fundamental, or base, quantities
- Macroscopic Level
- refers to how we perceive matter with our eyes, through the outward appearance of objects
- Density
- is the ratio mass to volume
- Significant Figures in M & D
- the result of multiplication and division may contain only as many significant figures as the least precisely known quantity in the calculation
- Gas
- distances between atoms or molecules are much greater than in a liquid
- Paradign
- a pattern of thinking about a field
- Kelvin Scale
- assigns a value of zero to the lowest possible temperature; the interval is the same size as the Celsius scale
- Substances
- a generic term for elements and compounds
- Kelvin from Celsius
- T(K) = t (°C) + 273.15
- Deduction
- using basic assumptions or premises to draw a certain conclusion that logically follows
- Extensive Property
- is dependent on the quantity of matter observed
- Solid
- atoms or molecules are in close contact, sometimes in a highly organized arrangement called a crystal
- Significant Figures (Exact Numbers)
- exact numbers can be considered to have an unlimited number of significant figures
- Molecule
- is the smallest entity having the same proportions of the constituent atoms as does the compound as a whole
- Chemical Property
- is the ability (or inability) of a sample of matter to undergo a change in composition under stated conditions
- Precision
- refers to the degree of reproducibility of a measured quantity
- Celsius (centigrade) Scale
- the melting point of ice is 0°C, the boiling point of water is 100°C, and the interval between is divided into 100 equal parts
- Composition
- refers to the parts or components of a sample of matter and their relative proportions
- Weight
- is the force of gravity on an object
- Atoms
- very tiny units that make up matter
- Compounds
- are substances comprised of atoms of two or more elements joined together
- Chromatography
- process that relies on the differing abilities of compounds to adhere to the surfaces of various solid substances
- Filtration
- the process of separating a solid from the liquid in which it is suspended
- Hypothesis
- is a tentative explanation of a natural law
- Systematic Errors
- built-in, or inherent, errors in measuring instruments
- Natural Law
- are concise statements, often in mathematical form, about natural phenomena
- Theory
- is a model or way of looking at nature that can be used to explain natural laws and make further predictions about natural phenomena