Chem Final Review Flashcards
Rules for Counting Significant Figures
1. Nonzero Integers
Nonzero integers are always significant.
Rules for Counting Significant Figures
- Zeros
a) leading zeros
Leading zeros are zeros that precede all nonzero digits. These do not count as significant figures.
ex. 0.0025 has two sig figs.
Rules for Counting Significant Figures
- Zeros
b) captive zeros
Captive zeros are zeros between nonzero digits. These always count as significant figures.
ex. 1.008 has four sig figs
Rules for Counting Significant Figures
- Zeros
c) Trailing zeros
Trailing zeros are zeros at the right end of the number. They are significant only if the number contains a decimal point. The number 100 has one sig fig, 1.00*10^2 has three sig figs.
100. has three sig figs.
Rules for Counting Significant Figures
3. exact numbers
this is the 2.54 cm in a inch kind of thing.
Rules for Significant Figures in Mathematical Operations
1. For Multiplication or division
The number of sig figs in the result is the same as the number in the least precise measurement used in the calculation.
ex. 4.56*1.4=6.38 –> 6.4
Rules for Significant Figures in Mathematical Operations
2. For addition or subtraction
The result has the same number of decimal places as the least precise measurement used in the calculation.
Celsius to Kelvin
T(celsius) + 273
Celsius to Fahrenheit
T(celsius)*(9/5) + 32
Law vs Theory
A law summarizes what happens, a theory is an attempt to explain why.
Daltons Atomic Theory 1 2 3 4
1) each element is made up of tiny particles called atoms
2) the atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways.
3) chemical compounds are formed when atoms of different elements combine with each other. A given compound always has the same relative numbers and types of atoms.
4) Chemical reactions involve reorganization of the atoms - changes in the way they are bound together, atoms not changed.
J. J. Thomson experiment
Cathode-Ray, discovered charge to mass ratio of electron
Milikan experiment
Oil Drop, discovered charge of electron
Rutherford experiment
Gold Foil, atoms have a dense center of positive charge, electrons around, a lot of space
c=
lambda*v
Using Planck’s constant
∆E=
nhv
E(photon)=hc/lambda
hc/lambda
principal quantum number (n)
integral values (1,2,3) as n increases, the orbital becomes larger and the electron spends more time farther from the nucleus. An increase in n also means higher energy, the electron is less tightly bound to the nucleus
This number is the coefficient so
3s^2, n=3
Angular momentum quantum number (l)
integral values from 0 to n-1 Related to the shape of the atomic orbitals. l=0, s l=1, p l=2, d l=3, f l=4, g
magnetic quantum number (ml)
Integral values between l and -l, including zero.
Value of ml is related to the orientation of the orbital in space relative to the other orbitals in the atom.
so if it’s 2p, ml -1, 0, +1
4s, 0
3d, -2, -1, 0, 1, 2
Electron configuration of copper
[Ar] 4s^1 3d^10
Electron configuration of chromium
[Ar] 4s^1 3d^5
Trend in atomic radius
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Trend in ionization energy
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Trend in electron affinity
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