Chemical Analysis Techniques: Flame Tests, Fingerprinting, Chromatography, and Titrations
Flame Tests
Different elements emit different colors when electric current is passed through them. This is due to the electron configuration within the atom. Chemists use this theory to analyze materials for the presence of certain elements. By observing the emitted colors, they can identify elements in an unknown substance. Traces of different metals are used in fireworks to produce various colors.
We can demonstrate this effect in the laboratory by heating various metal salts in a Bunsen flame.
Read MoreMatter, Atoms, and Electric Charge: A Physics Fundamentals
Mass and Matter
Mass is related to the amount of matter and measures the inertia of a body, exerting gravitational action. A body of 10 kg has twice the inertia of a body of 5 kg. The mass of Jupiter is about 310 times the mass of Earth, resulting in a 310 times larger gravitational force. Density is calculated as mass/volume. The mass of an object measures its inertia, while its weight on Earth is the force drawing it towards the planet.
Material Systems
A material body is any form of matter with
Read MoreMatter: Properties, States, and Mixtures in Chemistry
- Definition of Chemistry
Chemistry is the science of chemical phenomena and the internal structure of matter.
- Definition of Physics
Physics is the science of physical phenomena.
- Physical and Chemical Phenomena
Physical phenomena affect some properties of substances without transforming them into new ones. Chemical phenomena produce new substances with the disappearance of others.
- Definition of Matter
Matter is anything that has mass and occupies a volume.
- Definitions of Mass and Volume. SI Units of Measurement
Mass
Read MoreMixtures and Pure Substances: Properties and Separation
Mixtures and Pure Substances
Definitions
- Homogeneous Mixture: A mixture with components so small they appear uniform to the naked eye. Aqueous solutions are examples of homogeneous mixtures.
- Heterogeneous Mixture: A mixture where the components are visible, either with the naked eye or optical instruments.
- Mixture: Composed of two or more components with undefined proportions.
- Pure Substance: Matter with a definite and constant composition and distinct properties.
- Solution: A homogeneous mixture of two
Food Dehydration: Methods, Principles, and Moisture Analysis
Dehydration for Food Preservation
Dehydration reduces food’s water content to less than 13%. Advantages include excellent protection against spoilage as microorganisms cannot develop without water, enzymatic activity is inhibited, and chemical reactions slow down. Dehydration is optimal for products stored at elevated temperatures. To achieve maximum protection, remove virtually all water and store the food in tightly sealed containers, isolated from oxygen, light, insects, and rodents. Freeze-drying,
Read MoreUnderstanding Fire: Combustion, Classification, and Extinguishing Methods
Triangle of Fire
Combustion requires three elements: a substance that is oxidized, a substance that is reduced, and energy (activation energy, usually heat) to initiate the reaction. If any of these elements is missing, combustion will not occur.
Oxidant: Oxygen is the primary oxidizer in most combustion processes.
Fuel: Any substance capable of undergoing combustion or combining with oxygen to produce an exothermic reaction.
Heat: Energy required to start the reaction, often provided by ignition sources
Read More