Understanding Chemical Reactions and Thermodynamics
Test Results
- When two or more pure substances mix to form a gas or solution, absorption or release of heat occurs; this is called a reaction.
- Calor (This seems to be an error, likely intended to be ‘Specific Heat’). Specific Heat is the ratio of the specific heat capacity of a substance to the heat capacity of water, the latter measured at a temperature close to 17°C. Correct
- The energy balance is: energy that accumulates within the system, less energy consumed within the system. Correct
- The energy
Chemical and Physical Changes: Reactions and Laws
Physical Changes
Physical changes occur when some properties change, but the substances remain the same.
Chemical Changes
Chemical changes occur when some substances are transformed into others. There is an exchange of energy.
Causes of Chemical Bonds
The causes of chemical bonds are electromagnetic forces.
Chemical Reaction
A chemical reaction is the process by which chemical changes occur.
Chemical Links
Interactions are produced by electrons:
- Ionic Bond: Metal + Non-metal. The non-metal loses electrons,
Essential Laboratory Equipment and Techniques
Essential Laboratory Equipment
Measuring Devices
- Graduated cylinder: Measures volumes of liquids.
- Pipette (Total): Measures a precise volume of liquid for transfer.
- Pipette (Partial): Measures partial volumes of liquids.
- Burette: Measures the exact volume of a solution.
- Thermometer: Measures temperatures.
- Precision Balance: Measures masses of solid substances.
Containers and Supports
- Porcelain: Used to heat, melt, or evaporate solids or liquids.
- Florence flask: Heats liquids, directing vapors along a specific
Bohr’s Atomic Model: Postulates and Applications
Bohr’s Theory
Bohr’s Atomic Model
What did Bohr Do?
In 1913, Bohr applied quantum theory to Rutherford’s atom and proposed a model that explains the hydrogen atom’s emission and absorption spectrum. He produced a revolutionary theory.
What are the Postulates of Bohr’s Theory?
- The electron moves around the nucleus in specific circular orbits called energy levels or principal quantum levels.
- While the electron moves in the same energy level, it does not absorb or emit energy. The electron is in a steady
Understanding Plastics: Definition, Polymers, and Classification
Understanding Plastics
Today, plastic is used in our daily lives. It has replaced metal parts in the automotive industry and is used in construction, packaging, household appliances (washing machines, blenders, refrigerators, etc.). In the near future, it will be entering other branches of industry, for example, in medicine, such as joint replacement (artificial joints), games of all kinds, and sporting goods. As you can see, the plastic industry is in the process of growth. It is common to see pieces
Read MorePrintmaking Techniques: Etching, Halftone, and Ceramics
Halftone Printing
Halftone printing involves gradually raising the gray and white tones to eliminate roughness, similar to drypoint. It limits the number of prints due to the press crushing the roughness.
Halftone Features
- Amplitude and smoothness of the black.
- A unique engraving system that allows real chiaroscuro.
- Halftone engravings are recognized by a characteristic densely crosslinked derivative of graphing, particularly visible along the edges.
Etching
Etching is an indirect metal plate engraving
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