Enthalpy of Formation of Magnesium Oxide
The purpose of the experiment was to determine the enthalpy of formation of
Magnesium Oxide by applying Hesss Law and calculating enthalpy changes for the
reactions of Mg and MgO.
The materials we used for this exp
Calculating Avogadros Number by Comparing Atoms and Solid Round Objects
The purpose of the experiment was to calculate Avogadros number. In order to
find it we calculated the packing efficiency and the size ratio of beads and marbles.
The materials we use
Empirical Formula Calculation
Example 3.18 Obtaining an Empirical Formula from
A laboratory analysis of aspirin determined the following mass percent composition:
Find the empirical formula.
Stoichiometry the area of chemistry that deals with the
quantitative relationships between products and reactants in
Solving stoichiometry problems always requires the use of:
1. A balanced chemical equation (st
Periodic Properties of the Elements
Periodic properties properties whose values can be
predicted based on the elements position on the periodic
Properties of Gases
Particles are very far apart
Particles move around freely
Particles experience little or
no attractive forces
Properties of Liquids
Intermediate between gases
Explain how and why atoms attach together to form
Explain why some combinations of atoms are stable
whereas others are not.
Can be used to predict the shapes of molecules.
Can be used to predict the chemical and physi
Compound a substance containing two or more elements
that are chemically combined in a definite proportion by
Elements in compounds are always combined in wholenumber ratios.
Compounds, unlike elements, can be decomposed into
Properties of molecules are directly related to their shape.
Molecular shape depends on many factors.
The skeletal arrangement of the atoms.
The kind of bonding between the atoms.
Bonding theory allows us to predict molecular sh
The Beginnings of Quantum Mechanics
Until the beginning of the 20th century, it was believed that all
physical phenomena were deterministicthe present set of
conditions completely determines the future.
During the early 20th century, work done b
Physical Characteristics of Gases
Indefinite shape (assume the shape of their
Indefinite volume (expand to completely fill their
Mix evenly and completely when confined to the
same container (gas mixtures are always
The Nature of Energy
Energy the capacity of matter to do work.
Work the action of a force through a distance.
work = force distance
Heat the flow of energy caused by a difference in
Energy can be exchanged between objects through co
Early Theories on the Structure of Matter
Early models of the atom were developed by the Greeks.
Empedocles (490-430 B.C.) proposed matter was
composed of four basic elements: earth, air, water, and
Democritus (460-370 B.C.) proposed matte
The Study of Chemistry
Scientific method a systematic approach to
Hypothesis a tentative explanation for a set of
Law a concise statement of a relationship between