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CHEM 1251: Test 1 Vocabulary

Terms in this set (30)

Substance
form of matter that has definite composition and distinct properties. (elements or compounds)
ex. salt, iron, water, oxygen, CO2
Element
cannot be separated into simpler substances by chemical means
ex. iron, mercury, oxygen, hydrogen
Compound
made of atoms of 2 or more elements united in fixed proportions
ex. CO2
Mixture
combination of 2 or more substances
ex. mixed nuts, apple juice, milk, air
Heterogeneous Mixture
uniform throughout
ex. dissolving sugar in water
Homogeneous Mixture
composition is NOT uniform
ex. iron and sand mixed together b/c they both remain distinct
Physical Properties
can be observed and measured w/o changing the identity
ex. melting/freezing point, mass, color, density
Chemical Properties
must carry out a chemical change; the original substance will no longer exist
ex. rust, flammability, combustion
Extensive Property
depends on amount of matter
ex. mass, length, volume
Intensive Property
does NOT depend on the amount of matter
ex. density, temperature
Volume Displacement
subtract initial volume from the final volume
(Final-Initial=Displacement)
Accuracy
tells us how close a measurement is to the true value
Precision
tells us how close multiple measurements of the same thing are to one another
Atom
basic unit of an element that can enter into a chemical combination
Molecule
-combination of at least 2 atoms in a specific arrangement held together by electrostatic forces known as covalent bonds
-can be an element or a compound
Atomic Number
number of protons in the nucleus of each atom of an element
Mass Number
-found when you round the atomic weight to the nearest whole number ex. 83.80 to 84
- (# of protons) + (# of neutrons) = mass number
# of Protons
-the atomic number
-never changes
# of Electrons
-equal to the number of protons
- A +1 charge would mean the protons have 1 MORE than the electrons
- A -1 charge would mean the protons have 1 LESS than the electrons
# of Neutrons
mass # = (# of protons-# of neutrons)
OR
mass # - atomic #
Ion
an electrically charged atom
Ionic Compounds
-consists of cations and anions in an electrically neutral combination
-metal AND non-metal
***prefixes are NOT used
Molecular Compounds
-focus on binary compounds
-composed of only 2 non-metals
Cation
ions with (+) charge
Anion
ions with (-) charge
Naming Molecular Compounds
-use greek prefixes for both elements present
-add -ide to the root of the 2nd element
Naming Ionic Compounds (Fixed charged cations)
Cations w/ 1 possible charge: (Alkali metals, Alkaline earth metals, Ag^+, Al^3+, Cd^2+, Zn^2+)
1. name metal 1st
2. if monatomic, add -ide
3. if polyatomic, use name of anion
Naming Ionic Compounds (Multiple charged cations)
Cations w/ more than 1 possible charge: (usually transition metals, Tin (Sn), Lead (Pb), requires stock notation)
1. determine if molecule is molecular or ionic
2. if ionic, name the cation 1st with stock notation 1st
3. if anion is monatomic, use -ide
4. if polyatomic, use polyatomic name
Naming Oxoanions (that end in -ate)
1. the ion with 1 more O atom than the -ate ion is called the per...ate ion
2. the ion with 1 less O atom is called the -ite ion
3. the ion with 2 fewer O atoms than the -ate ion is called the hypo...ite ion
Naming Oxoacids
-ate ion = ...ic acid
-ite ion = ...ous acid
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