Chemistry Principles: Matter, Mixtures, and Laws
Principles of Chemistry
Matter and Chemistry
Mass is the fundamental characteristic of matter.
Chemistry is for studying the nature of matter and changes that affect nature.
Physical changes do not alter the nature of substances; chemical changes do.
Pure Substance
A pure substance has a definite, constant composition, specific physical and chemical characteristics, and cannot be separated into other substances by physical methods.
Mixture
A mixture has variable composition and properties related to its
Read MoreKey Concepts in Thermodynamics and Thermochemistry
- Calorie: A unit of power based on the specific heat of water, used to express the energy value of food.
- State Function: A macroscopic physical quantity that characterizes the state of a system in equilibrium.
- Internal Energy: The total change in internal energy equals the sum of the energy supplied to the system as heat and work.
- Heat of Reaction: The heat absorbed or released during a chemical reaction at constant pressure.
- Heat: The amount of energy a thermodynamic system can exchange with its environment.
Fundamental Concepts of Thermodynamics and Energy Changes
What is Thermodynamics?
Thermodynamics is the part of physics that studies the heat and work exchanges accompanying physicochemical processes. When these processes are chemical reactions, the specific branch studying them is called thermochemistry. The energy exchanged in a chemical reaction can manifest as heat, light, electrical energy, etc.
Thermodynamic Systems
System, Environment, and Universe
A thermodynamic system is the specific part of the universe isolated for study of its physicochemical
Read MorePhysical Chemistry Concepts: Definitions and Applications
Nernst Distribution Law
The Nernst Distribution Law describes the equilibrium distribution of a solute between two immiscible liquid phases. It states that at a constant temperature, the ratio of the concentrations of the solute in the two liquids is constant, provided the solute has the same molecular form in both phases.
Limitations include deviations due to solute association or dissociation in one phase, and non-ideal behavior at higher concentrations. Modifications often involve using activities
Read MoreUnderstanding Atomic Theory: Dalton to Nuclear Fusion
Understanding Atomic Theory
· Dalton’s Atomic Theory: Matter is composed of indivisible and indestructible particles called atoms. Each chemical element consists of identical atoms, distinct from those of other elements. Chemical compounds form through the union of atoms from different elements in fixed ratios.
· Chemical Element: A substance that cannot be broken down into simpler substances, consisting of only one type of atom (refer to the Periodic Table).
· Compound: A substance that can be
Read MoreFire Extinguisher Types and Their Limitations
1. Limitations of Foam Extinguishers
- In electrical fires, water content poses a risk to personnel due to conductivity, especially in manual applications. Automatic systems are more effective than water alone.
- Incompatibility between some foams and powder extinguishers can cause foam breakdown when applied simultaneously, particularly with obstacles on the burning liquid’s surface.
- Not suitable for pressurized gas fires (butane, propane, etc.) due to high evaporation and swelling.
- Reacts with highly