Understanding Matter, Mass, Weight, and Energy Concepts
Understanding Matter, Mass, Weight, and Energy
All we can see and touch is matter. There are also material things we cannot see, like air.
We note that matter occupies a certain portion of space we call volume. In the case of air, this is not obvious, but the next experience will help us prove it.
Mass
Mass represents the coefficient of inertia of a body, i.e., the resistance the body opposes to changes in its state of motion or stillness.
Weight
Weight is the measure of the gravitational force acting on an object.
States of Matter
Solid State
Solids have a constant shape and volume. This is because the particles that form them are held together by forces of attraction so great that they have almost fixed positions.
Liquid State
Liquids, like solids, have a constant volume. In liquids, the particles are linked by attractive forces that are less than those in solids. For this reason, the particles in a liquid can move freely. The number of particles per unit volume is very high, so collisions and friction between them are very frequent.
Gaseous State
Gases, like liquids, have no fixed shape, but unlike them, their volume is not fixed. They are also fluid, like liquids.
In gases, the forces holding the particles together are very small. In a gas, the number of particles per unit volume is also very small.
Miscibility
Miscibility is the ability of a substance to dissolve in another. It is a qualitative data point. Substances are separated into “miscible” and “immiscible” pairs.
Viscosity
Viscosity is the property of a fluid that tends to oppose its flow when a force is applied. High viscosity fluids have a certain resistance to flow; low viscosity fluids flow easily.
Pure Substance
A pure substance cannot be separated into other substances by any mechanical means.
Element
An element is a substance that, by any means, either physical or chemical, cannot be separated or broken down into simpler substances.
Compound
A compound is a substance formed by the joining of two or more elements of the periodic table in a fixed ratio. A key feature is that it has a chemical formula.
Mixture
A mixture is formed by the union of varying amounts of substances that are not chemically combined.
Heterogeneous Mixture
Heterogeneous mixtures are those whose components are distinguishable to the naked eye, allowing one to appreciate more than one physical phase.
Homogeneous Mixture
Homogeneous mixtures are those whose components are not identifiable to the naked eye, i.e., we see a single physical phase.
Solution
Solutions result from a mixture of two or more different pure substances whose union does not produce a chemical reaction but only a physical change. A substance (solute) dissolves in another (solvent), forming a single phase. The components can be separated using physical means.
Energy
Energy is a property associated with objects and substances and is reflected in the changes that occur in nature.
Potential Energy
Potential energy is a scalar potential associated with a force field (or, in elasticity, a stress tensor field).
Kinetic Energy
Kinetic energy is energy that arises in the phenomenon of motion.
Exothermic
Exothermic refers to a chemical or physical process that occurs with the release of energy. Combustion is an exothermic reaction that follows light and heat.
Endothermic
Endothermic refers to a chemical or physical process that requires an input of energy as heat to take place.
Exergonic
An exergonic process is one that releases energy.
Endergonic
Endergonic processes are those chemical processes that require energy input to be able to perform.