Chemistry Ch.1-4 Flashcards
Density
- If we compare the mass of the object to its volume.
- D=m/v
- Sink=more dense
- float=less dense
Atomic # & Protons
above symbol
Electrons
= to protons
Mass #
protons + neutrons
Ions
By losing electrons, a metal atom forms an ion, which has a positive charge
Physical Change
Matter’s state or appearance will change, but its composition remains the same.
Chemical change
The original substance is converted into one or more new substances, which have different physical and physical properties.
Specific heat
The amount of heat needed to raise the temp of exactly 1g of a substance be exactly 1 degree C.
- Pg. 61
- Lower heat heats up faster and cools quickly.
- Heat= mass X temp change X specific heat
Write formulas from names
- Write the symbol
- Determine the charge
- Determine the common multiple of the charge
- Write subscripts after the respective symbols. Use ( ) when you have multiple polyatomic ions.
ide
A compound made up of only 2 elements.
Ate
The oxidation # is higher
Ite
The oxidation # is lower
SI Units
- The official system of measurement throughout the world.
- Length = meter (m)
- Volume = Cubic meter (m^3)
- Mass= kilogram (kg)
- Temp = kelvin (K)
- Time = Seconds (s)
Isotopes
-Atoms of the same element that have the same # of protons, but different #s of neutrons.
Heating Curve
The temp is shown on the vertical axis and the addition of heat is shown on the horizontal axis.
Cooling curve
A diagram of the cooling process in which the temp decreases as heat is removed.
Dipole- dipole attractions
Occur between the positive end of one molecule, and the negative end of another. (usually liquids at room temp)
Hydrogen bond
Occurs between the partially positive hydrogen atom of one molecule and a lone pair of electrons on a nitrogen, oxygen, or fluorine atom in another molecule. (strongest type of dipole-dipole bond)
Dispersion force
Very weak attraction, occur between nonpolar molecules. (instantaneous, very short, usually gasses at room temp)
Electronegativity
the ability of an atom to attract the shared electrons in a bond.
Electronegativity trend
Increases going horizontally R to L in periodic table.
Decreases going down.
Dipole
A polar covalent bond that has a separation of charges.
SEE PG. 150!
look at it
Nonpolar covalent bond
A bond between atoms with identical or very similar electronegativity values.
Polar covalent bond
When bonds are between atoms with different electronegativity values, the electrons are shared unequally.
Ionic bond
Lose or gain electrons.
Share electrons
(metal and nonmetal)
Covalent bond
Share electrons
2 nonmetal
Valence electron
= group # ??
