Final Exam Flashcards
How do we determine if substance is a pure substance?
When we talk about a pure substances we refer to the submicroscopic level
How do we determine if a substance is a mixture?
Mixtures are visible to us (macroscopic level)
Within pure substances we have…
elements and compounds
Withing mixtures, we have…
homogenous mixtures and heterogeneous mixtures
What are the 2 types of properties?
Physical and chemical
What is the difference between physical and chemical?
physical properties include: density,mass appearance, color, freezing/boiling point.
Chemical properties include: flammability, reactivity (chemical changes convert one substance into another, physical does not)
What are the rules for sig figs in addition and subtraction?
Our answer has as many decimal places as the least exact measurement
What are the rules for sig figs in multiplication and division?
Your answer has as many sig figs as the least exact measurement
What are the rules for sig figs in logs?
The number of sig figs in the parenthesis (starting value) equals the number of decimal places
ex: log(4.1 * 10^-3) = 2.39
What are the rules for sig figs in antilogs?
The number of decimal places in the antilog equals the number of sig figs in the result
ex: antilog (1.325)= 10^1.325= 21.1
How do we find celsius given Fahrenheit
C = (F-32) * 5/9
How do we find Fahrenheit given celsius?
F = C * 9/5 + 32
How do we find Kelvin?
If we are given Celsius just add 273. If we are given Fahrenheit simply convert to celsius first and then add 273
What is specific heat?
It measures the ability of a substance to absorb heat
What is the formula of specific heat?
(Heat) / mass * change in temp.
What happens if we change the number of protons?
We change the element
What happens if we change the number of neutrons? What does it form?
We change the mass forming an isotope
What happens if we change the number of electrons? What does it form?
We change the charge of an element forming an ion
Elements are identified by their _____ which is equal to the number of protons
Atomic number
How do we write the notation for an element?
(Mass on top) (atomic number on bottom) and element symbol on the right
What are the two types of ions?
Cations and Anions
What is a cation?
It has a positive charge and it is formed by losing electrons
Which group of elements are most likely to be cations?
metals
What is an anion?
A negatively charge element formed by gaining electrons.
Which group of elements are most likely to be anions?
non-metals
How do we calculate average atomic mass?
Since we are given two isotopes and their percent of abundance, take the corresponding percentage of their atomic mass and add.
What is the law of constant composition?
Elements always combine in the same proportion and formula.
How do we find mass percent?
(part/whole) * 100
How is Daltons Atomic Theory outdated?
It stated that atoms of the same element were the same mass and atoms of different elements had different mass.
All matter is made of indivisible particles called atoms
Atomic Spectra helps us understand that electron energy is…
quantizied
The areas where an electron will most likely be is called a
orbital
Orbitals have a __ % probability
90%
What are the 3 types of subshells and how many orbitals do each have?
S subshells have 1 orbital
p subshells have 3 orbitals
d subshells have 5 orbitals
Each orbital can hold how many electrons?
2
What is the ground state electron configuration?
1s,2s,2p,3s,3p,4s,3d,,,
Alkali metals are in group _
Alkaline metals are in group _
Halogens are in group _
Noble gases are in group _
Alkali metals are in group 1
Alkaline metals are in group 2
Halogens are in group 7
Noble gases are in group 8
What is electronegativity?
It is a value that describes the extent to which atoms pull electrons.
Which element has the highest electronegativity value?
Fluorine
Which group has overall higher electronegativity values?
Nonmetals, they are more likely to pull electrons toward themselves
What is a non-polar covalent bond?
When we have 2 atoms that have a similar or identical electronegativity value, electrons are shared equally
What is a polar covalent bond?
When we have 2 different electronegativity values between atoms, sharing is unequal
The sharing of electrons is what type of bond?
Covalent
What is an ionic bond?
When electrons are completely transferred due to the difference in electronegativity values
What are the rules for naming ionic bonds?
The cation (metal) retains its name and the nonmetal's ending changes to -ide The only exception is polyatomic ions (retain their name)
What are the rules for naming covalent bonds?
The ending of the second element will change to-ide.
Covalent compounds always use prefixes (except for mono on first)
The only exception to this is diatomic molecules (they retain their name)
What are the 7 diatomic elements?
Hydrogen, Oxygen, Fluorine, Chlorine, Nitrogen, Iodine, Bromine
Why do we have to memorize transition metal charges?
Because they arent predictable
What are the charges for Chromium? (Cr)
2+ and 3+
What are the charges for Iron? (Fe)
2+ and 3+
What are the charges for copper? (Cu)
1+ and 2+
What are the charges for mercury? (Hg)
Hg(2) 2+ and 2+
What are the charges for tin? (Sn)
2+ and 4+
What are the charges for lead? (Pb)
2+ and 4+
How do we name binary compounds with transition metals?
No prefixes
Metals retain name, nonmetal changes to ide
Roman numerals are needed for the charge
How do we name covalent molecules?
Add prefixes (except for mono on first element) 2nd element ending changes to ide Diatomic molecules retain their name
What are the first 10 prefixes?
1: mono
2: di
3: tri
4: tetra
5: penta
6: hexa
7: hepta
8: octa
9: nona
10: deca
How do we know if a substance is an acid?
It will have an H in the beginning of the formula
What are the rules for binary acids?
Prefix will be hydro
Second element becomes ic
Add acid at end
EX: hydrochloric acid = HCl
What are the rules for polyatomic acids?
No Hydro prefix If ending was ate it turns to ic If ending was ite it turns to ous Add acid EX: H2SO4= sulfuric acid
If there are 2 bonds around the central atom the electron geometry is _______, the molecular geometry is _______. The bond angle is _______
Linear, Linear, 180
If there are 3 things around the central atom but only 2 bonds, the electron geometry is ______, the molecular geometry is _______. The bond angle is ______
trigonal planar, bent, <120
If there are 3 things around the central atom and 3 bonds, the electron geometry is ______, the molecular geometry is _______. The bond angle is _______
trigonal planar, trigonal planar, 120
If there are 4 things around the central atom but only 3 bonds, the electron geometry is ______, the molecular geometry is _______. The bond angle is _____
tetrahedral, trigonal pyramidal, <109.5
If there are 4 things around the central atom but only 2 bonds, the electron geometry is ______, the molecular geometry is _______. The bond angle is _______
tetrahedral, bent, <109.5
If there are 4 things around the central atom and 4bonds, the electron geometry is ______, the molecular geometry is _______. The bond angle is _______
tetrahedral, tetrahedral, 109.5
How do we know if a compound is polar?
We compare their electronegativity values, draw a lewis structure and make sure the molecule’s polarity isn’t canceled by symmetry.
How is symmetry unbalanced in a bond?
When we have lone pairs around central atom or when there are no identical groups around it.