Chapter 1 Review
Megan Do & Matt Choi
The Study of Chemistry
• Chemistry is the study of properties of
materials and changes that they undergo.
• Can be applied to all aspects of life.
The Atomic and Molecular Perspective
of Chemistry
Matter
• Is the physical material of the universe.
• Has mass and occupies space.
Elements
• Are made up of unique atoms, the building of matter.
Molecules
• Are combinations of atoms held together in specific shapes.
• Properties relate to composition and structure present.
Classifications of Matter
Solids, liquids and gases are the three forms of matter called the state
of matter.
• Gas – no fixed volume or shape, conforms to shape of container,
compressible; molecules far apart, move at high speeds, collide
often
• Liquid – volume independent of container, rigid, incompressible;
molecules closer than gas, move rapidly but can slide over each
other.
• Solid – volume and shape independent of container, rigid,
incompressible; molecules packed closely in definite arrangement
Pure Substances/Mixtures
Pure Substances
• Are matter with fixed compositions and distinct
proportions
• Are elements or compounds
Mixtures
• Are a combination of two or more pure substances
• Each substance retains its own identity
Elements/ Compounds
Elements
• Are pure substances
Compounds
• Are combination of elements
Law of Constant Proportions
• A compound always consists of the same
combination of elements
Example
• Water is always 11% H and 89% O
Properties of Matter
Physical properties
• Measured without changing the substance.
Chemical properties
• Describe how substances react/change to form different
substances.
Intensive properties
• Don’t depend on amount of substance present.
Extensive properties
• Depend on quantity of substance present.
Physical and Chemical Changes
Physical Change
• Substance changes physical appearance
without altering its identity.
Chemical Change
• Substance transforms into a chemically
different substance.
Separation of Mixtures
Filtration
• Removes solid from liquid
Distillation
• Boil off one or more components of the mixtures
Chromatography
• Exploit solubility of components
Unit of Measurement
• Many Properties of matter are quantitative.
Mass
• Is a measure of the amount of material in an object.
Temperature
• Measure of hotness or coldness of an object.
• Celsius - water freezes at 0°C ant boils at 100°C
• Kelvin – Water freezes at 273K and Boils at 373K
• Zero is the lowest possible temperature.
• K= °C+273K
Derived SI units
Volume
• equals (Unit of length)ᵌ=mᵌ
Density
• Equals Mass divided by volume
Example: g/mL or g/L
Significant Figures
Rules
- Nonzero numbers & zeros between nonzero
numbers = SIGNIFICANT
- Zeros before first nonzero digit = INSIGNIFICANT
- Zeros at end of number after decimal point =
SIGNIFICANT
- Zeros at end of number before a decimal point are
ambiguous
Dimensional Analysis
• Method of calculation utilizing a knowledge of
units
Uncertainty in Measurement
Precision
• How well measured
quantities agree with
each other
Accuracy
• How well measured
quantities agree with
“true value”
Review
• Find the density of 4.75 L of H₂SO₄
• Are these measurements accurate or precise if
the actual value is 2.7 cm?
• How many atoms of hydrogen can be found in
45 g of ammonia?