Chemistry CH 1 & 2 Flashcards
Charles Law describes?
At a constant pressure, when you have a known mass of gas, the volume of the gas is directly proportionately to the temperature.
- Heat goes up, then vol goes up
- Heat goes down, then vol goes down
What is the formula for Charles Law?
V1/T=V2/T2
F to C
C= (F-32) x 5/9
Or
C= (F-32)/1.8
C to F
F= 9/5C + 32
or
F = 1.8C + 32
Log (a x b) =
Log (a) + Log (b)
Log (a/b) =
Log (a) - Log (b)
Lob (a^b) =
b x Log (a)
Any quantity (except zero) raised to the zero will equal?
1
Any quantity (except zero) to the -1 power is equal to?
The reciprocal of the quantity
2^ -1 = 1/2^1
When powers are multiplied, the exponents will be added or subtracted?
added
When powers are divided, the exponents will be added or subtracted?
subtracted
What is the mantissa?
the scientific notation where there is only one number to the left of the decimal.
1.5 x 10^3
What is the formula for slope intercept?
y = mx + b
y= vertical axis (dependent variable)
x= horizontal axis (independent variable)
m= slope line
b = intercept (the value of the function where it crosses the y-axis)
What is the formula to find the slope (m)
m = (y2-y1)/(x2-x1)
note: the slope of a line (m) depicts the change in the dependent variable (y) as the independent variable (x) is changed
What are significant figures?
Digits in a measured value that have a physical meaning and can be reproducibly determined
Exact numbers are?
Numbers not obtained using measuring devices. easily countable, no question as to the value
ex. 12 cm = 1 ft
12 ducks
These measurements have an infinite number of significant figures
What are the 4 rules when dealing with significant figures?
- Nonzero digits are always significant
- Captive zeros are always significant
- Leading zeros (despite the decimal place) are never significant
- Trailing zeros are only significant when the number contains a decimal point (ex: 1.50 vs 100; 1.50 has 3 sigfigs and 100 has 1 sigfig)
How many sigfigs do you keep when adding or subtracting?
Keep the smaller number of decimal places
How many sigfigs do you keep when multiplying or dividing?
Keep the smaller number of sigfigs
Define accuracy
The agreement between experimental data and the true value.
In other words, how close a measurement is to the true/accepted value
Define precision
The agreement between replicate measurements.
In other words, how close measurements of the same item are to each other
Can accuracy be improved?
Accuracy can be improved by making replicate measurements and taking the average of those measurements
Can precision be improved?
Repeated measures do not improve precision.
Precision can be quantified by standard deviation. The smaller the SD the greater the precision
The SD is the square root of the data set’s variance
giga is
1 x 10^9
G
mega is
1 x 10^6
M
kilo is
1 x 10^3
k
deci is
1 x 10^-1
d
centi is
1 x 10^-2
c
mili is
1 x 10^-3
m
micro is
1 x 10^-6
u
nano is
1 x 10^-9
n
1in = ? cm
2.54cm
1mi = ? km
1.609 km
1mi = ? ft
5,280 ft
1 lb = ? kg
0.454 kg
Correctly stated as 1 lb = 4.45 N
1 lb = ? N
4.45 N
1 lb = ? oz
16 oz
1 oz = ? g
28.35 g
1 grain = ? mg
64.80 mg
1 L = ? dm^3
1 dm^3
1 gal = ? L
3.79 L
1mL (cc) = ? cm^3
1 cm^3
Kelvin temperature scale begins at?
absolute zero (coldest)
no temp lower than 0k
notice, no reported degrees
On a celsius scale how do you calculate for kelvin?
K = C + 273.15
What is Density?
Density is the ratio of the mass of an object to its volume
d = mass/volume = m/v
What is specific gravity?
The ratio between (density of an object / density of water)
Specific gravity only equals density when the units of measure are g/mL because the density of water is 1g/mL.
No units used in specific gravity because it is a RATIO
What is the density of water?
1.0 g/mL or 1.0g/cm^3
1000kg/m^3
8.33 lb/gal
What is matter?
Anything that has a mass and occupies space; doesn’t have to be visible
How many atoms to form an element
a single atom
How many atoms to form a compound
two or more atoms
What are atoms comprised of
Protons, neutrons, and electrons
What is the SI units for atoms
atomic mass units (amu)
1 amu = ? kg
1.66 x 10^-27 kg
1 mol = ? amu
1 amu
What are ions?
Ions are atoms or a group of atoms bonded together that have a net electrical charge
This charge can be obtained by adding or removing electrons
Charge or cations
protons > #electrons
(+) charge
Charge for anions
protons < #electrons
(-) charge
Define molecules (molecular compound)
Group of atoms chemically bonded together into a discrete unit by covalent bonds
Contains ONLY NON-METALS
Electrically NEUTRAL
Define Ionic Compounds
Contains (+) charged ions and (-) charged ions
Contains METALS & NON-METALS
Ionic compounds are NOT molecules
What is the difference between physical property and chemical property?
Physical property can be observed or measured without chemical change (ex color)
Chemical property describes the chemical changes the material tends to undergo (ex gases are flammable)
Define a pure substance
Materials that cannot be physically separated into simpler components
Ex: Elements are pure substances
T or F
Substances are compounds only
False
Substances can be either a compound or an element
If substances are a compound, then can be chemically separated into its elemental components. Elements are pure substances and cannot be further separated
What makes up a mixture
Comprised of 2 or more pure substances
Can be resolved into simpler components through physical processes
Homogenous mixtures are
uniform in chemical and physical properties
Heterogenous mixture
Exhibits distinct phase boundaries between its components
Ex: emesis
Define phase boundary
A demarcation where the chemical and/or physical properties of the sample change
The mass of an atom is the sum of what
Protons and Neutrons
Represented as an integer
1 neutron = ? amu
1.0087 amu
or 1.6749 x 10^-27 kg
1 proton = ? amu
1.0073 amu
or 1.6726 x 10^-27 kg
Elements are always
Electrically neutral
Therefore, each atom must have an equal # of (+) protons and (-) electrons
Define Isotopes
Have the same atomic number but different mass number.
In other words, same # protons but different # neutrons
What does Dalton’s Atomic Theory include?
1) Elements are composed of tiny atoms
2) Compounds are formed by bonding of atoms in a fixed ratio
3) Chemical rxns do not create, destroy, or change atoms; they recombine into a new substance
What are the 3 laws used in Dalton’s Atomic Theory?
1) Law of Conservation of Mass - no detectable change in the total mass occurs during a chemical rxn
2) Law of Definite Proportions - Different samples of a pure compound always contain the same elements in the same proportion by mass
3) Law of Multiple Proportions - some elements can combine to give more than one compound
What are polyatomic ions?
Polyatomic ions are considered ionic compounds as well.
They contain 2 or more non-metals plus a metal with an electrical charge (either + or -)
How would you name a molecular substance?
- Name each element
- Indicate how many of each is present with a prefix multiplier (mono, di, try, tetra, etc…)
- Add the suffix “-ide” to the last element name
Ex: N2S3 -> Dintrogen trisulfide
mono is
1
di is
2
tri is
3
tetra is
4
penta is
5
hexa is
6
hepta is
7
octa is
8
If a transitional metal forms more than one cation, how do you name it?
You need to name the metal, then indicate the charge on the cation with roman numerals in parentheses
ex. Fe3+ - iron (III) cation
How do you name monatomic anions?
Add the suffix “-ide” to the stem name
ex:
Cl- —> Chloride ion
S2- —> Sulfide ion
P3- —> Phosphide ion
How do you name monatomic cations?
Add cation or ion at the end of the name
*note, there are no simple cations with charges of +4
Ex: Cu 1+ —> Copper cation or Copper ion
How do you name polyatomic ions?
Some ions like SO4^2- and SO3^2- differ only in a single atom. In these cases, the larger # is given the suffix “-ate” while the smaller # is given the suffix “-ite”
SO4^2- would be sulfate ion
SO3^2- would be sulfite ion
How do you name a hydrate ion?
name the ion then add “hydrate” at the end
Ex: CuSO4 * 5H2O - Copper (II) sulfate pentahydrate
What is an electrolyte
A substance that dissolves in water to give a solution that conducts electricity
What is Avogadro’s Number?
Conversion factor between particles and moles
6.02 x 10^23 particles/mol
What is a mole
Quantity of material, analogous to a dozen. It is an amount of a substance that contains exactly as many particles as there are in exactly 12g of Carbon-12.
What does particle mean?
It could mean molecules, atoms, ions, or electrons
1m = ? cm
100 cm
1s = ?ms
1000ms
Molecular formula for ammonia
NH3
Ionic formula for ammonium
NH4+
Molecular formula for Methane
CH4
Molecular formula for propane
C3H8
Molecular formula for nitrous oxide
N2O
1 cm^3 = ? m
0.01 m
Or
10^-2
1micrometer (um) = ? nanometers (nm)
1,000nm
