Exam review study guide Flashcards
Rules for sig figs
Rule 1
- All non-zero digits are significant (Examples- 2,546 (4SF), 978 (3 SF)
Rule 2
- Zeros in front of a number are not significant (Examples- 0202 (3SF) 0.00234 (3SF)
Rule 3
- Zeros between non-zero are significant (Examples - 3,004 (4SF) 0.02305 (4 SF), 7.05 x 10 ^ -5 (3SF)
Rule 4
- Zeros at the end of a number are significant if there is a decimal point in the number (Examples 200 (1SF) 200. (3SF) 0.046700 (5 SF)
-Density calculation
Density = Mass (G) / Volume (ml)
Precent error calculation
|number experimental D - number of actual D over Number Of actual D| x100
Physical property
Quality or condition that can be observed or measured without changing the substance composition
Chemical properties
The ability of a substance to undergo specific chemical changes
Physical change
Some properties change, but not to chemical composition
Chemical change
The chemical composition of the substance changes
Element-
composed of atoms, that cannot be broken down into simpler substances by chemical means
Compound
A thing that is composed of two or more separate elements
Pure substance
A single substance made up of only one particle
Mixture-
two or more substances that are mixed together but not chemically combined
-Diatomic elements
Molecules composed of two atoms
Proton, neutron , electron
Protons
- A particle with a positive electrical charge
Neutrons
- A particle with a neutral charge
Electrons
- A particle with a negative charge
What is an atom
The smallest particle of an element that retains its identity in a chemical reaction
Cation
An Ion with a positive charge
Anion
An Ion with a Negative charge
How do you find the charge of an ion
The charge of an Ion is the number of protons minus number of electrons
-Isotopes
Isotopes - Are atoms with the same number of protons but different number of neutrons
Metals -
Good conductors of electricity, all malleable, almost all are solid
Non-metals -
Poor conductors of electricity, most are gasses, any solids are brittle
Metalloids
Act like either metals or nonmetals depending on condition
- Nuclear Fission -
the process where the nucleus of an atom splits into two or more smaller nuclei and other particles
- Nuclear Fusion -
the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy
- Radioactive Decay -
the property of some unstable atoms to spontaneously emit nuclear radiation, usually alpha particles or beta particles often accompanied by gamma-rays.
-Writing nuclear equations
- The sum of the mass of the reactants = the sum of the , mass of the product
- The sum of the changes of the reactants = the sum of the charges of the products
-Wavelength, frequency, and energy calculations when given equations.
Wavelength
– distance between corresponding points of two consecutive waves.
Frequency
– the number of waves that pass a given point in one second.
Short wavelengths =
– high frequency, high energy– Vise\versa
-Electrons and energy levels
In order for an electron to reach the next energy level they need an exact amount of energy
S sublevel -
Shape -
How many electrons -
what level does it begin in -
Spherical in shape
Can hold 2 electrons
Begins in principal energy level 1
P sublevel -
Shape -
How many orbitals -
How many electrons -
what level does it begin in -
- Dumbbell shaped
- Has three different orbitals x, y, and z
- Each orientation holds 2 electrons for a total of 6 electrons
- Begins in principal energy level 2
D sublevel -
Shape -
How many orbitals -
How many electrons -
what level does it begin in -
Clover leaf shape
Has 5 different orbitals
Each holds 2 for a total of 10 electrons
Begins in principal energy level 3
F sublevel -
Shape -
How many orbitals -
How many electrons -
what level does it begin in -
- Crazy complicated shape
- 7 different orbitals
- Each holds 2 electrons for a total of 14 electrons
- Begins at principal energy level 4
-Rules for placing electrons in orbitals. (Don’t need to know names, just how they work)
- Electrons occupy the lowest energy orbital first
- Each orbital may describe at most two electrons, each with opposite spins
- Each degenerate orbital is filled with one electron, all with the same spin, before going
Back to pair up
- Valence electrons (what they are and knowing how many an element has)
- Outermost electrons (In the highest principal energy level) the last S and P added
-Periodic trends (The trend and the WHY behind the trend)\
- The periodic table shows us many trends for the elements, It displays trends for atomic size, ionization energy, ionic size, and electonegativity.
-Lewis structures (How to draw for elements and compounds, the terms used for different types of electrons (nonbonding electron pair, unpaired electron, etc.), etc.)
1 - Count up total number of valence electrons for compound (For polyatomics add/subtract electrons based on charge)
2- Draw in the central atom and single bond all of the other atoms to it single bonds = 2 electrons
3 - Fill in valence electrons for bonded atoms
4 - Extra electrons go on the central atom. Each atom should have 8 except for hydrogen
5 - If you don’t have enough electrons move unshared pairs to make double or triple bonds
6 - Put square brackets around the diagram for polyatomic ions with the charge written polyatomic ions with the charge written outside the brackets as a subscript
-Molecular geometry
- Linear
- Bent
- Triangle planar
- Triangle pyramidal
- Tetrahedral
Polarity and formal charges
The slight electrical charges on dissimilar atoms are called partial charges
-Ionic vs. covalent compounds (what they are made of, properties, etc.)
Ionic
- Made up of a nonmetal and metal
Covalent
- Made up of 2 non metals
-Intermolecular force and its impact on physical properties
an attractive force that arises between the positive components (or protons) of one molecule and the negative components (or electrons) of another molecule.
-Be able to calculate molar mass for a given chemical
- Atomic mass of an element
-Be able to do mole conversions between mass, moles, and particles
1 mole = 6.02 x 10 ^23 representative particles
Whatever unit you start with must be at the bottom
-Percent composition calculations
- %MASS = element / compound x100
-Be able to determine an empirical formula when given percent composition
- Write percent as a mass (g)
- Convert to moles
- Divide by the smaller value
- If still not whole number multiply
- Write empirical formula
- Divide sample mass by empirical molar mass multiply, by empirical formula formula to get molecular formula
