Chemistry 100
-
Upload
demetrius-glover -
Category
Documents
-
view
28 -
download
0
description
Transcript of Chemistry 100
![Page 1: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/1.jpg)
Chemistry 100
Chapter 2Atoms, Molecules and Ions
![Page 2: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/2.jpg)
Law of Conservation of Matter
By 1800, chemists had noted that the mass of reactants equals the mass of products - provided you capture any escaping gas
Matter is not created or destroyed in a chemical reaction
![Page 3: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/3.jpg)
Law of Constant Composition
Chemists (notably Proust) The relative amount (percentage) of
each element in a compound was the same no matter how the compound was made
These two laws lead Dalton to revive the Atomic Theory Matter is made up of small, indivisible
particles
![Page 4: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/4.jpg)
Dalton’s Atomic Theory
An element is composed of atoms. All atoms of a given element are the
same. Atoms of different elements are different
and have different properties.
![Page 5: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/5.jpg)
Dalton’s Theory-II
Atoms are not changed, created or destroyed in a chemical reaction.
Compounds are the combination of more than one element. A given compound has the same relative
number and kind of atoms.
![Page 6: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/6.jpg)
Law of Multiple Proportions
Accorrding to Dalton’s Theory Two elements (A and B) form two distinct
compounds The amounts of B combining with a fixed amount
of A would be a small whole number ratio. Water: 1 g hydrogen + 8 g oxygen Hydrogen peroxide: 1 g hydrogen +16 g
oxygen
![Page 7: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/7.jpg)
Atomic Structure
Roentgen discovered X-rays (1895) Becquerel discovered radioactivity
(1896) J. J. Thompson discovered the
electron (1897) Rutherford classified radioactivity
emissions: alpha (), beta () and gamma ()
![Page 8: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/8.jpg)
Alpha, beta, gamma
Rutherford’s findings: Alpha are positive particles (+2) ;
heavier than electrons Beta are high speed electrons;
negatively charged particles (-1) Gamma are neutral rays Alpha particles are nucleus of He
atom
![Page 9: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/9.jpg)
Thompson’s Model
“Plum pudding” modelA cloud of positive charge holding the
negatively charge electrons in place
![Page 10: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/10.jpg)
Rutherford’s alpha experiment
Scattering of alpha particles by gold foil
Most particles were undeflected Some were deflected by large angles
![Page 11: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/11.jpg)
Rutherford’s Explanation
![Page 12: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/12.jpg)
Rutherford’s Model
Centre - the nucleus - is small but positively charged
Most of the atom is empty spaces Electrons rotate about the nucleus -
like the solar system
![Page 13: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/13.jpg)
Modern Model
Additional experiments showed Nucleus consists of protons (positive) and
neutrons (neutral) Electrons (negative) exist around the
nucleus Number of protons = number of
electrons
![Page 14: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/14.jpg)
Mass of Elementary Particles
Protons and neutrons have a mass of about 1 amu
Electrons have very small mass Most of the mass of an atoms comes
from nucleus (1 amu is 1.66054 10-24 grams)
![Page 15: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/15.jpg)
Quantum Mechanical Model
![Page 16: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/16.jpg)
Atomic Mass & Atomic Number
A
SyZ
A is Mass Number,protons + neutrons
Z is Atomic Number,number of protons
![Page 17: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/17.jpg)
Isotopes
All atoms of a given element have the same number of protons. All Carbon atoms have 6 protons (and 6 electrons).
The number of protons is different for each element.
Atoms of a given element that differ in the number of neutrons are called isotopes.
Examples : carbon-12 and carbon-14
C126 C146
![Page 18: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/18.jpg)
Atomic Masses
By international agreement, the carbon-12 atom is defined as having a mass of exactly 12 atomic mass units (amu’s).
All atomic masses are referenced to this standard.
![Page 19: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/19.jpg)
The Periodic Table
A typical entry in the periodic table
Ca20
40.078
Atomic mass
Atomic number
![Page 20: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/20.jpg)
Periodic Table (II)
Elements in the periodic table are arranged in Groups or families – they have similar
chemical and physical properties Metals – towards the left Nonmetals – towards the right Metalloids – in the middle region
![Page 21: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/21.jpg)
Atomic Masses in the Periodic Table
Question: why is the mass of C in the periodic table reported as 12.01 amu and not as 12.000 … amu, exactly?
Another example: the atomic mass of Cl is = 35.453 amu’s. We would expect Cl to be 35 amu?
![Page 22: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/22.jpg)
Ionic Compounds
Tables of common ions in textbook (pages 60 and 63).
Ionic compounds Cation name followed by anion name,
e.g., sodium bromide (NaBr) Multiple ion types
FeCl2 – iron (II) chloride FeCl3 – iron (III) chloride
![Page 23: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/23.jpg)
Binary Molecular Compounds
Binary compounds containing two nonmetals name of the first element in the formula
followed by the stem of the name of the second element with the suffix -ide.
The number of atoms of each element in the compound is indicated by a prefix.
mono di tri tetra
1 2 3 4
Some common names must be committed to memory.
Examples – nitrous oxide, N2O, and nitric oxide, NO.
![Page 24: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/24.jpg)
Formulas and Names of Acids
An acid usually is a compound of hydrogen and a nonmetal or a polyatomic anion.
Treat the hydrogen atoms of the acid as H+ ions.
For acids containing monatomic anions, When these acids are found in water solution,
add the prefix hydro- and the suffix -ic to the stem of the name of the anion
Hydrofluoric acid (HF), hydrochloric acid (HCl)
![Page 25: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/25.jpg)
Acids From Polyatomic Anions
If the anion name ends in ‘ate’, the ‘ate’ in the name of the anion is replaced by ‘ic acid ’ The acid of the sulfate ion is sulfuric acid (H2SO4) The acid of the nitrate ion is nitric acid (HNO3)
If the anion names end in ‘ite’, we change the suffix to –ous and add the word acid. The acid of the nitrite is called nitrous acid, HNO2
The acid of the hypochlorite ion is called hypochlorous acid, HClO
![Page 26: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/26.jpg)
Average Atomic Masses
Most elements in nature exist as mixtures of isotopes.
Atomic masses reported in the periodic table - weighted averages of the different isotopes.
The amount of each isotope in a sample of as an element may vary considerably with the source of the sample. This is the reason why some elements in the
periodic table have few significant figures for their mass.
![Page 27: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/27.jpg)
Organic Compounds
Many organic compounds have complex three dimensional structures chains, and/or rings branches.
The highlighted groups are called functional groups. They are primarily responsible for the
chemical and some physical properties of the molecules.
![Page 28: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/28.jpg)
Methane (CH4)
Ethane (C2H6)
Propane (C3H8)
Butane (C4H10)
Alkanes
C
H
HH
H
C
H
HH
C
H
HH
CH
HH
C
H
H
C
H
HH
CC
CH
C
H
HH
H
HH
H
HH
![Page 29: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/29.jpg)
Methanol (CH3OH)
Ethanol (CH3CH2OH)
1-Propanol (CH3CH2CH2OH)
2-propanol (CH3CH(OH)CH3)
Alcohols
C
H
OHH
H
C
H
HH
C
H
HOH
CH
HH
C
H
H
C
H
OHH
CC
CH
H
HH
HOH
H
H
![Page 30: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/30.jpg)
Methyl Amine (CH3NH2)
Dimethyl amine ((CH3)2NH)
Ethyl Amine (CH3CH2NH2)
Organic Amines
C
HNH2
HH
NH
CH3
CH3
C
H
HC
H
NH2H
H
![Page 31: Chemistry 100](https://reader033.fdocuments.us/reader033/viewer/2022051401/56813731550346895d9ebe1b/html5/thumbnails/31.jpg)
Formic (Methanoic) acid (HCOOH)
Acetic (Ethanoic) Acid (H3COOH)
Propionic (Propanoic) Acid (H3CCH2COOH)
Organic Acids
C
O
OHH
C
H
HH
C
O
OH
CH
HH
C
H
H
C OH
O