quiz 3 Flashcards
q=MC∆T
q= energy IN JOULES M= mass IN GRAMS C= heat capacity in j/gc ∆T= temp change IN CELSIUS
thermal equilibrium
in the process of heat transferring from one substance to another, if given enough time, the end result will always be that they are the same temperature
(no conservation of temp bc temp is not energy)
in the example of the water and the lead block, their relationship can be summarized by
q water= -q lead block
as the ∆T for the water is positive while it is neg for the lead block
atomic theory
all matter is composed of atoms
elements are composed of one type of
atom
john daltons atomic theory
- each element is composed of tiny indestructible particles called atoms, which are all conserved (neither created nor destroyed) during a chemical change, just rearranged into different combinations
- if two atoms are of the same element, they will be completely identical. if its 2 of different elements, they’ll be different
- atoms combine in simple, whole-number ratios to form compounds. no element is found as a fraction of an atom
plum pudding model
- atom’s mass is spread throughout the atom
- positive charges are spread throughout the atom
- neg charges are balanced out by positive charges
proposed by thompson, disproven by his protege rutherford
Nuclear Model
- atom’s mass is concentrated at the nucleus
- positive charge is concentrated at the nucleus
- neg charges balanced out by pos charges (that didnt change from plum pudding model)
proposed by rutherford to correct his mentor thompson’s plum pudding model
subatomic particles
compose atoms
- protons with +1 charge
- neutrons with no charge
- electrons with -1 charge
mass of a neutron vs proton
almost exactly the same (around 1 amu, or 1.67*10^-27 kg)
the atomic number of an element
- the top number on an entry in the periodic table
- indicates the # of protons that element will always have (thats what makes it that element)
- also known as Z
the atomic mass
- the bottom number on an entry in the periodic table
- indicates the mass in amu of one atom of that element
- is a WEIGHTED average that takes the natural abundance of each isotope into account
rows in the periodic table are referred to as
periods (7 of them)
columns in the periodic table are referred to as
groups (18 of them)
4 types of compounds
- ionic
- metallic
- covalent
- acid
metals
can be found to the left and under the "stairs" (the staircase which "potter" (Po) lives under) and are 1. ductile (can be drawn into wires) 2. malleable 3. luster (shiny) 4. good conductor of heat 5. good conductor of electricity
ions
atoms that lose or gain electrons to form charged particles
groups w predictable charges as ions
- alkali metals: +1
- alkaline earth metals: +2
- halogens: -1
mass number
- given by variable “A”
- sometimes given as a superscript to the left of the element symbol
- indicates the number of protons + neutrons
isotopes
- atoms that have same # of protons, but different # of neutrons.
- same atomic number, different mass number
to find weighted average
multiple each mass by its respective abundance (as a decimal, not %) and then add those products
to find mass of a compound
determine the amount of each atom present, that multiple each atom’s atomic mass by the amount of atoms present, then add the products
ionic compounds
- composed of ions with pos or neg charges, always have a net charge of 0 (neutral)
- start with a metal and end w a nonmetal
metallic compounds
are made entirely of metal
covalent compounds
are not split into charges, so not split into metal (cation) and nonmetal (anion)
acids
always start with “H”
alkali metal family
farthest left group
alkaline earth metal family
group to the right of the alkali metal group
halogen family
group to the left of the noble gases
noble gas family
farthest right group, non-reactive
mass of an electron
.00055 amu, or .00091*10^-27 kg. it’s 1/2000 of a proton or neutron
crystalline
a solid form of matter which has a long range repeating order
an x-to-y ratio
is calculated as x/y, and expressed as a whole number.
ex: x=12, y=3, their ratio is 4.
melting point
the temp at which a solid becomes a liquid.
below the temp it is a solid, and above, it is a liquid.
law of constant composition
all samples of a given compound have the same proportions of their constituent elements
