Midterm Exam (Chapters 1-7) Flashcards
Quantitative observations
Measurements (consist of a number and a unit)
Qualitative observations
Visual, sensual observations that do not involve numbers
Metric prefixes
10^6 = Mega (M) 10^3 = Kilo (k) 10^2 = Hecto (h) 10^1 = Deka (da) 10^0 = BASE UNIT 10^-1 = Deci (d) 10^-2 = Centi (c) 10^-3 = Milli (m) 10^-6 = Micro (u) 10^-9 = Nano (n)
Uncertainty in a measurement
We have to estimate the last digit of measurements due to the limits of measuring devices. Uncertainty depends on the precision of the measuring device.
Converting from Celsius to Fahrenheit
TºF = 1.8TºC + 32
Density formula
d = m/V
Density of water
1 g/mL
Rule for adding/subtracting significant measurements
Round to the lowest number of decimal places
Rule for multiplying/dividing significant measurements
Round to the lowest number of significant figures
Separation techniques that can be used to separate mixtures
Distillation - volatility
Filtration - size/state of manner
Chromatography - polarity
Centrifugation - density (homogeneous mixtures)
Law of multiple proportions
When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 g of the first element can always be reduced to small whole numbers.
Nuclide symbol
A = mass number (total number of protons and neutrons) Z = atomic number (number of protons) X = element symbol
Isotope
Atoms with the same number of protons but different numbers of neutrons
Cation
Positive ion formed by losing an electron
Anion
Negative ion formed by gaining an electron
Chemical formula
Illustrates molecules, where the element symbols are used to indicate the types of atoms present, and subscripts are used to indicate the relative numbers of atoms
General properties of metals
- Efficient condition of heat and electricity
- Malleability, ductility
- (Often) lustrous appearance
- Tend to use electrons to form positive ions (cations)
Limiting reactant
The reactant that is completely consumed when a reaction is run to completion
Strong acids
HCl HF HBr HNO3 H2SO4 HClO4
Strong bases
LiOH NaOH KOH Ca(OH)2 Sr(OH)2 Ba(OH)2
Molarity
Moles of solute per volume of solution in liters
Solubility rules
SOLUBLE:
NO3^-1, Group IA Elements, NH4^+1 (NO EXCEPTIONS)
Cl^-1, Br^-1, I^-1 (EXCEPT Ag^+1, Pb^+2, Hg2^+2)
SO4^-2 (EXCEPT Ba^+2, Pb^+2, Hg2^+2, Ca^+2)
INSOLUBLE:
OH^-1 (EXCEPT Na^+1, K^+1, Ba^+2, Sr^+2, Ca^+2)
S^-2, CO3^-2, CrO4^-2, PO4^-3 (EXCEPT Group IA, NH4^+1)
Four types of oxidation-reduction reactions
- Synthesis
- Decomposition
- Combustion
- Single-replacement
Oxidation state rules
- Atom in an element = 0
- Monatomic ion = Charge of the ion
- Oxygen = -2 in covalent compounds (-1 in peroxides)
- Hydrogen = +1
- Fluorine = -1
- Sum of oxidation states in compounds = 0
- Sum of oxidation states in polyatomic ions = Charge of the ion
Gases have ________ densities.
Low
Gas laws
Boyle: Indirect relationship between pressure and volume
Charles: Direct relationship between temperature and volume
Avogadro: Direct relationship between number of moles and volume
Ideal gas
Exactly follows the ideal gas law (PV=nRT), has particles so small compared with the distances between them that the volume of the individual particles can be assumed to be negligible (zero). The particles are in constant motion, so the collisions of the particles with the walls of the container are the cause of the pressure exerted by the gas. The particles are assumed to exert no forces on each other, so they are assumed to neither attract nor repel each other. The average kinetic energy of a collection of gas particles is assumed to be directly proportional to the Kelvin temperature.
When do gases not behave ideally?
When temperatures are low and pressures are high. Real gases have high gas particle concentrations, attractive forces, and actual pressures are lower than ideal pressures.
STP
Standard temperature and pressure (273 K and 1 atm)
Rate of effusion
The speed at which a gas is transferred into an evacuated chamber through a tiny orifice
Rate of effusion for gas 1/rate of effusion for gas 2 = √M2/√M1 (Inverse ration of the square roots of the molar masses)
What influences the intermolecular attractions among gas molecules?
A high concentration of gas molecules means that it is more likely that a pair of gas particles will be close enough to attract each other. When gas particles come close together, attractive forces occur, which cause the particles to hit the wall very slightly less often than they would in the absence of these interactions. The amount of moles of gas particles per liter (n/V) affects that.
BIG WHOPPER
1 atm = 760 torr = 760 mmHg = 101.325 kPa = 101325 Pa = 14.69 psi = 29.92 inHg
Heat (q)
\+ = A quantity of energy flows into the system via heat (ENDOTHERMIC) - = A quantity of energy flows out of the system via heat (EXOTHERMIC)
Work (w)
\+ = Surroundings do work on the system (energy flows into the system) - = System does work on the surroundings (energy flows out of the system)
Specific heat capacity
The energy required to raise the temperature of one gram of a substance by one degree Celsius
Heat capacity
Heat absorbed per increase in temperature
Standard enthalpy of formation
The change in enthalpy that accompanies the formation of 1 mole of a compound from its elements with all substances in their standard states
Hess’s Law
In going from a particular set of reactants to a particular set of products, the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps.
Types of radiation
Gamma rays, x-rays, ultraviolet, VIBGYOR, infrared, microwaves, radio waves
Atomic orbital
A specific wave function for an electron in an atom. The square of this function gives the probability distribution for the electron.
Principal energy level
Describes the size and energy of an orbital
Sublevel
Describes the shape of atomic orbitals
e.g.: s, p, d, f
Ionization energy
The energy required to remove an electron from a gaseous atom or ion
Electron affinity
The energy change associated with the addition of an electron to a gaseous atom
Periodic trends
Ionization energy:
First ionization energy increases as we go across a period from left to right.
The first ionization energy decreases in going down a group.
Atomic radius:
Decreases going across a period.
Increases going down a group.
Electron affinity:
When we go down a group, electron affinity becomes more positive (less energy released)
Energy levels available to the electron in the hydrogen atom
E = -2.178 x 10^-18 J (Z^2/n^2) Z = nuclear charge (1) n = energy level (integer)
Energy of a photon
Ephoton = hc/λ = hν
Mass of a light particle
m = h/λv
v = velocity
Formula for the speed of light
λv = c
Speed of light = 2.9979 x 10^8 m/s
