Chemistry Mid-Term Prep
What is a heterogenous mixture?
A mixture in which the composition is not uniform throughout
What is a homogenous mixture?
A mixture in which the composition is uniform throughout
Which groups correspond to the following? Alkali Metals = ? Alkali Earth Metals = ? Transition Metals = ? Inner transition metals = ? Lanthanides = ? Actinides = ? Metalloids/Semi-metals = ? Other Metals = ? Other Non-Metals = ? Halogens = ? Noble Gases = ? Gases at room temperature = ? Liquids at room temperature = ? Solids at room temperature = ? Man-made elements = ?
Alkali Metals = Group 1(minus H) Alkali Earth Metals = Group 2 Transition Metals = Groups 3-12 Inner Transition Metals = The F block(Lanthanides and Actinides) Lanthanides = Top row of the f block, 57-71 atomic numbers Actinides = Bottoms row of the f block, 89-103 atomic numbers Metalloids/Semi-Metals = Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Polonium Halogens = Group 17 Noble Gases = Group 18 Gases @ room temp = Noble Gases, Fluorine, Chlorine, and Oxygen Liquids @ room temp = Bromine and Mercury Solids @ room temperature = everything that was not stated as liquid or gas Man-Made Elements = = 93-118 in atomic numbers, technetium, and promethium
What is a temperature curve?
A curve that represents the changes that occur when heat is added or removed from a sample of matter. Increased heat results in more fluidity so more towards the liquid end of the phases and decreased heat results in less fluidity so more condensed matter
What is proper lab attire and behavior?
Full sleeves and pants, don't play around when you shouldn't, just use common sense
What is the mass number of an element?
How many protons AND neutrons an element has
ionic bond vs covalent bond
Ionic: between two non-metallic ions, utilizing the charges, the extra electrons from one side are shared with the other atom, filling it's missing electron spots Covalent: between a metal and a non-metal, single, doubly and triple bonds formed between pairs of electrons to create more atomic stability
What is the trend for ionization energy? Also define it
Ionization Energy = The amount of energy needed to remove an electron from an atom The trend is the same as electronegativity since the smaller the radius, the closer the atom is to the nucleus, hence a stronger force of attraction keeping it there
How do you determine the name/symbol for ions?
Name: 1. Cations - Just write ion after the element 2. Anions - Same as cations but change the ending of the element to -ide Symbol: You know this shit. But remember, you have to add the charge above it
How to draw lewis dot structures for ions AND neutral atoms
Neutral atom lewis dot structures are just the elements surrounded by the number of valence electrons it has. An ion is just the element surrounded by 8 valence electrons if it's a negative charge and 0 if it's a positive charge BUT, you put it inside two brackets and write the charge like an exponent on the outside
What is the difference between a physical and chemical change?
Physical changes are simply phase changes Chemical changes are when the compound itself acc changes
How to determine the number of protons, neutrons, and electrons in an atom/ion?
Protons = Look at the atomic number Neutrons = Subtract the atomic number from the mass number Electrons = All non-ionic atoms have the same number of protons as electrons. If it IS an ion, just use the charge to subtract or add to the atomic number
What were the contributions of Dalton, Thomson, Rutherford, and Bohr?
Dalton: Atomic Theory = All elements are made of different numbers of atoms, atoms of different elements can physically and chemically join together to form compounds in simple whole-number ratios Thomson: Discovered that electrons are negatively charged using a cathode ray tube, determined the charge to mass ratio of electrons, and hypothesized that atoms were like "plum puddings" with electrons and protons evenly sprinkled throughout the atoms Rutherford: Aimed positive alpha particles at gold foil to prove the "plum pudding" idea wrong, hypothesizing a positively charged, dense, middle Bohr: Proposed a model of the atom in which the electron was able to occupy only certain orbits around the nucleus. This atomic model was the first to use quantum theory, in that the electrons were limited to specific orbits around the nucleus.
What kind of waves does light consist of?
Electromagnetic Waves
What is the trend for electronegativity? Also define it
Electronegativity = The ability of an element to attract electrons The trend is the reverse of atomic radius due to the fact that as radius gets smaller, the force of attraction is farther outward from the atom as the atom itself is smaller
What are the bond angles of the five molecular shapes?
Linear = 180º Bent = 105º Trigonal Planar = 120º Trigonal Pyramidal = 107º Tetrahedral = 109.5º
What are the changes of state?
Liquid => Solid: Freezing Liquid => Gas: Vaporization Solid => Liquid: Melting Solid => Gas: Sublimation Gas => Liquid: Condensation Gas => Solid: Deposition
How do you determine the number of atoms in a compound?
Look at the subscript and add up?
What are the SI Base Units?
Measurement: 1. Mass = Grams(g) 2. Time = Seconds(s) 3. Length = Meters(m) 4. Temperature = Kelvin(k) 5. Quantity = Mole(mol) 6. Current = Ampere(A) 7. Luminous Intensity = Candela(cd) Prefix: 1. Tera(T) = 10^12 2. Giga(G) = 10^9 3. Mega(M) = 10^6 4. Kilo(K) = 1,000 5. Hecto(H) = 100 6. Deka(Da) = 10 7. Deci(d) = 10^-1 8. Centi(c) = 10^-2 9. Milli(m) = 10^-3 10. Micro(μ) = 10^-6 11. Nano(n) = 10^-9 12. Pico(p) = 10^-12 Ex of prefixes: I have 2 dekagrams = I have 200 grams
In general, which side of the periodic table are metals and non-metals located, respectively?
Metals = Left Non-metals = Right
Why do ionic bonds only occur between metals and non-metals?
Metals wanna give up electrons and non-metals want to take so this makes balancing chargers possible
How to calculate average atomic mass
Multiply the mass of each isotope by its natural abundance, expressed as a decimal(it's just how much percent of the world's supply of said element is that isotope. Just a percent presented as a decimal), and then add the products
What is an ion?
Atoms lowing or gaining electrons to become a noble gas
What are isotopes?
Atoms of the same element with different numbers of neutrons
How do you determine formula given name?
Ionic : balance the charges will determine subscript of the elements Covalent : turn the elements into symbols and the prefixes into subscript
How do you determine the names/symbols for compounds?
Ionic Bond: Between a metal and a non-metal 1. Name => Symbol: Balance the charges and write down the reflective subscript. Keep it in the order of the word form 2. Symbol => Name: Take the two symbols and write their word forms down(in order of the symbols). Then change the ending of the second element to -ide if it's not a polyatomic
What is Capillary Action?
The attraction of the surface of a liquid to the surface of a solid
Rule for sig figs when adding or subtracting?
The least number of digits after the decimal point out of all the numbers involved represents the number of digits after the decimal point of the final answer.
How do you determine sig figs in a measurement?
To determine the number of significant figures in a number use the following 3 rules: Non-zero digits are always significant. Any zeros between two significant digits are significant. A final zero or trailing zeros in the decimal portion ONLY are significant
What is the rule for naming ionic compounds?
Unless it's a polyatomic, you just add -ide to the end of the second element,
What is the rule for naming covalent compounds?
Use the two element names with the numerical prefixes, but if it's one in the first element, leave it blank
What does VSEPR stand for and mean?
Valence Shell Electron Pair Repulsion => Electrons tend to push away from each other This explains why lone pairs pull the atom up because they don't. They push the other atoms away *The reason the electrons in the lone pair don't push away from each other is because the FoA of the shared Nucleus is stronger than the FoA of VSEPR so they are forced to be like that*
polar vs nonpolar covalent bonds
When one atom is more electronegative than the other atom in the bond, drawing in electrons in the bond, making it negatively charged and the other positively charged If the electronegativity difference is <0.4 = non-polar Between 0.4-1.9 = Polar >1.9 = Ionic
What is surface tension?
a force that tends to pull adjacent parts of a liquid's surface together, thereby decreasing surface area to the smallest possible size
What is the separation line between metals and non-metals?
Starts under and drops down and to the right in a staircase pattern; left of silicon, under silicon, left of arsenic, under arsenic, etc. all the way down to the left side of Oganesson
Given energy = E, and plank's constant = h, what are all the wavelengths and frequencies formulas to remember?
c = λν E = hν E = mc^2 c = 3.00 x 108 m/sec h = 6.626 x 10-34 J • sec => Planck's Constant Hz = 1/sec
How do you calculate the density of an object?
mass divided by volume
What is a binary compound?
A compound composed of two different types of elements
The four properties to measure when measuring waves and their definitions
Amplitude => The wave's height from the origin to the crest Wavelength(λ) => The distance between two crests of a wave Frequency(v) => The number of wave cycles to pass a given point per unit of time Speed(c) => The rate at which a wave travels aka the speed of light. This is a constant. c = 3.0 x 10^8 m/s
What is a neutral atom?
An atom with the same number of protons and electrons, aka no charge
Describe the process when colors are emitted in a flame test
As a substance is heated up, the electrons get excited with kinetic energy and move around a bunch. Result, when they calm down and return to their energy levels, they gotta release that energy. They release it as visible light
Differentiate boiling, evaporation, sublimation, and freezing?
Boiling = Vaporization where the entire liquid is being heated at the same time Evaporation = Vaporization where the entire liquid is vaporizing from the top Sublimation = The direct change from solid to gas. This happens at temperatures where liquids cannot exist Freezing = Going from liquid to solid due to a lack of heat
What is the normal boiling point and normal freezing point of water?
Boiling Point: 100ºC Freezing Point: 0ºC
What are the different types of Crystalline Solids and their characterisitics?
1. Ionic Crystals: - Ions arranged in a regular pattern - Hard - Brittle - Good Insulators - High Melting Points 2. Covalent Network Crystals: - Each atom is covalently bonded to the nearest neighboring atom 3. Metallic Crystals: - Metal Cations surrounded by a sea of electrons - High Conductivity 4. Covalent Molecular Solids: - Covalently bonded molecules held together by IMF - Low Melting Point - Easily Vaporized - Soft - Good Insulators
What are the five types of molecular shapes?
1. Linear: symmetrical line of atoms(Ex. H2) 2. Bent: Linear but a lone pair on the element in the middle so it pushes everything away a lil bit(Ex. CH2) 3. Trigonal Planar: Symmetrical three way split bonds(Ex. CH3) 4. Trigonal Pyramidal: Trigonal Planar but a leftover lone pair pulls the molecule up(NH3) 5. Tetrahedral: A linear but four bonds instead of two so it's still symmetrical(CH4)
Describe solids, liquids, and gases(shape, volume—indefinite or definite?)
Solids: Shape and Volume are definite Liquids: Volume is definite but shape is indefinite Gases: Volume and shape are indefinite
What is the atomic number of an element?
The number of protons it has
How does a phase diagram work?
The triple point represents the point at which the solid, liquid, and vapor conditions coexist The critical point represents the point after which the liquid and the gas are indistinguishable
Why do elements in the same group have similar properties?
They have the same valence electrons, hence some similarities
What are the Roman numerals in naming for?
They represent which of the different charges certain transitional metals have are being used
What is a polyatomic ion?
ions that are made of more than one atom
How do you recognize the number of valence electrons an element has?
Count how many elements left to right on it's row it is
How do you know if a molecule is polar?
1. Bond Polarity => Must have polar bonds or a lone pair on the central atom 2. Molecular Geometry => The molecule must not be asymmetrical *You test one first, if it doesn't work, you alr know two doesn't. If one works, then test two. If two also works out, it's polar*
What is the speed of light?
3.00 x 10^8 m/s
Which subatomic particle contributes most to the position of the elements on the periodic table and also their properties?
Electrons
What is the trend for atomic radius?
Going from the top right corner to the bottom left corner, it gets larger
What are the different types of IMF? How do you determine which is in situation? What is the hierarchy of strength in IMFs
IMFs: 1. London Dispersion: Instantaneously created and disappearing dipoles caused by the movement of electrons in a molecule. Occurs in all atoms since all atoms have moving electrons 2. Dipole-Dipole: A force of attraction between two dipoles(polar molecules) due to the negative side of one molecule being attracted to the positive side of another 3. Hydrogen Bond: NOT A BOND. A force of attraction when a Hydrogen bonded to N, O, or F is attracted to a lone pair in another molecule How to determine which types of IMFs are in which situation: 1. London Dispersion = Always existent 2. Dipole-Dipole = Present if it is a polar molecule 3. Hydrogen Bond = Has to be a polarized Hydrogen attached to N, O, or F The Hierarchy of Strength in IMFs: 1. Hydrogen Bonds 2. Dipole-Dipole 3. London Dispersion
How can you determine if a molecule is polar?
If the bonds in the molecule aren't symmetrical or there are lone pairs not distributed symmetrically
REVIEW THAT YOU REMEMBER ELECTRON CONFIGS CAUSE IT'S HARD TO EXPLAIN IN WORDS
REVIEW THAT YOU REMEMBER ELECTRON CONFIGS CAUSE IT'S HARD TO EXPLAIN IN WORDS
Electromagnetic Radiation in order of smallest to largest . . .
Radiowaves, microwaves, infrared waves, visible light, ultraviolet waves, x-rays, and gamma rays
What are the rows and columns on the periodic table called?
Rows = Periods Columns = Groups
What is viscosity?
The resistance of a liquid to flow
What are the unique properties of water? What causes water to have these properties?
Water has an extremely high melting point, boiling point, heat of vaporization, and surface tension. Why? Water aka H2O has an extremely high IMF strength due to having TWO Hydrogen Bonds any phase change requires large gains in energy or large drops in energy
Rule for sig figs in multiplication and division?
When you take the final sig figs, you have to do the lowest sig figs in the numbers involved. If you have for example, something like 800*3, you can't write 2400 as 2 in one sig fig, so you write 2 * 10^3. 2000 is not the same as 2400 but that's just what you have to do
How to write the symbol for an element?
Write down the letters(s), mass number in the top left corner, atomic number in the bottom left corner, charge in the top right corner
Can you compare phase change points with IMFs?
Yes, cause the higher the IMFs, the more energy needed to make electrons move. Phase changes are all about electron mobility and breaking free of IMFs so the higher the IMF, the more energy/heat you need. Ex. Well, when IMFs go UP, there is more FoA holding electrons in place, hence a higher amount of kinetic energy/heat to move the electrons around. We need more heat means a higher boiling point.
How do you determine the charge for an ion?
You count back or forward(whichever is closer) till you hit a noble gas BUT, certain transition metals have multiple, random charges so you need to just look at the PT for that
