Introduction to Chemistry
Introduction to Chemistry
What is Chemistry?
Chemistry is the study of changes in matter, as well as its structure and properties.
The Origins of Chemistry
Alchemy played a significant role in the development of chemistry. Alchemists, in their pursuit of turning lead into gold and achieving immortality through the philosopher’s stone, made a crucial contribution by meticulously documenting their observations.
Matter and Energy
Matter is anything that occupies space and has mass.
Energy is the capacity to do work or accelerate mass, but it is not matter itself.
Properties of Matter
Properties of matter describe the appearance and behavior of different types of matter.
- Physical properties: Characteristics observable without altering the material’s composition (e.g., color, density, electrical conductivity).
- Chemical properties: Describe the types of reactions a material can undergo (e.g., flammability, ability to rust).
The Scientific Method
The scientific method is a cyclical process used to acquire and apply new knowledge. It involves five steps:
- Make observations.
- Define a problem.
- Formulate a hypothesis (proposed solution).
- Perform an experiment.
- Analyze the results.
This cycle is continuous and never truly ends.
Scientific Hypothesis and Experimentation
A scientific hypothesis must be testable through experimentation (observable phenomena). A well-designed experiment must be accurate, controlled, and repeatable.
Variables in Experiments
Variables are factors that can change during an experiment and must be measured.
- Independent (manipulated) variable: The variable deliberately changed by the experimenter.
- Dependent (responding) variable: The variable observed for changes in response to the independent variable.