chem 108, chapter 1
Chapter 1: Measurement and the Properties of Matter
Author: Martin McCarthy
Source: McGraw Hill LLC
Importance of Chemistry
Learning changes everything.
Chemistry is integral to various fields:
Health and Medicine
Sanitation systems
Surgery with anesthesia
Vaccines and antibiotics
Gene therapy
Energy and the Environment
Fossil fuels
Solar energy
Nuclear energy
Materials and Technology
Polymers, ceramics, liquid crystals
Room-temperature superconductors
Molecular computing
Food and Agriculture
Genetically modified crops
“Natural” pesticides
Specialized fertilizers
The Study of Chemistry
Utilizes systematic approaches for research through the scientific method.
The Scientific Method
Hypothesis: A tentative explanation for observations.
Law: A concise statement of consistent relationships in experiments.
Theory: A unifying principle that explains a body of facts or laws.
International System of Units (SI)
Base quantities and their respective units:
Length: meter (m)
Mass: kilogram (kg)
Time: second (s)
Electrical current: ampere (A)
Temperature: kelvin (K)
Amount of substance: mole (mol)
Luminous intensity: candela (cd)
SI Unit Prefixes
Common prefixes for SI units:
exa- (E): 10^18
peta- (P): 10^15
tera- (T): 10^12
giga- (G): 10^9
mega- (M): 10^6
kilo- (k): 10^3
deci- (d): 10^-1
centi- (c): 10^-2
milli- (m): 10^-3
micro- (µ): 10^-6
nano- (n): 10^-9
pico- (p): 10^-12
femto- (f): 10^-15
atto- (a): 10^-18
Volume and Density
Volume: SI derived unit is cubic meter (m³).
Conversion:
1 cm³ = 1 mL
1 L = 1000 mL
Density:
Formula: Density (d) = mass (m) / volume (V)
SI unit is kg/m³
1 g/cm³ = 1000 kg/m³
Densities of some substances (at 25°C):
Hydrogen: 0.0000899 g/cm³
Water: 1.00 g/cm³
Gold: 19.3 g/cm³
Temperature Scales
Conversion formulas:
Kelvin to Celsius: K = °C + 273.15
Celsius to Fahrenheit: °F = (°C × 9/5) + 32
Significant Figures
Numbers are significant based on certain rules:
Non-zero digits are significant.
Zeros between non-zero digits are significant.
Leading zeros are not significant.
Trailing zeros in a decimal are significant.
Dimensional Analysis
A method for unit conversion:
Identify conversion factors needed.
Carry units throughout the calculation.
Ensure all unwanted units cancel out.
Examples and Problem Solving
Calculations involving density, conversions between units (lbs to grams, liters to milliliters).
Practical applications of chemical principles to everyday situations, demonstrating the relevance of chemistry in life.