Current location - Education and Training Encyclopedia - Educational Knowledge - What are the nine knowledge points of chemistry?
What are the nine knowledge points of chemistry?
The nine knowledge points of chemistry are as follows:

1. When a substance is dissolved in water, it is usually accompanied by changes in energy. This energy change can be felt by hand or measured by thermometer.

2. When the saturated solution of a substance is crystallized at variable temperature, its solute mass fraction becomes smaller (only the solute decreases and the solvent remains unchanged); When evaporating and crystallizing at constant temperature, the mass fraction of solute remains unchanged (saturated solution at this temperature is still obtained). Therefore, crystallization occurs and the solute mass fraction of the solution does not necessarily change.

3. Alloy: A substance with metallic characteristics, which is formed by fusing one metal with one or more other metals (or metal with nonmetal).

4. Solution: A uniform and stable mixture formed by dispersing one or more substances into another substance is called a solution.

5. The judgment of solute and solvent includes water. Water is a solvent, and liquid is soluble in liquid. Without water, a large amount is a solvent.