Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The Particle Theory of Matter states that all matter is composed of tiny particles. The arrangement and energy of these particles define the state: Solid, Liquid, or Gas.
Physical properties are characteristics that can be observed without changing the substance's identity, such as density, , , and electrical conductivity.
Density is the mass per unit volume of a substance. It is a constant for a pure substance at a given temperature and is expressed as .
Metals are typically shiny (), (can be hammered into sheets), (can be drawn into wires), and are excellent conductors of heat and electricity.
Non-metals are generally when solid, have lower compared to metals, and act as electrical and thermal insulators.
Chemical properties describe how a substance reacts with others. For example, the reaction of Magnesium with Oxygen: .
Solubility refers to the ability of a solute to dissolve in a solvent. Factors affecting solubility include temperature and the nature of the and .
📐Formulae
💡Examples
Problem 1:
A block of unknown metal has a mass of and a volume of . Calculate its density and identify if it could be Aluminum (Density of Aluminum is ).
Solution:
Explanation:
By dividing the mass () by the volume (), we get a density of . Since this matches the known density of Aluminum, the metal is likely Aluminum.
Problem 2:
Describe the change in particle behavior when ice () is heated to become liquid water ().
Solution:
The particles gain , vibrate more vigorously, and eventually overcome the strong forces of attraction holding them in a fixed .
Explanation:
In a solid, particles are in a fixed arrangement. Heating provides energy, allowing particles to slide past one another in the liquid state, though they remain close together.
Problem 3:
An object has a density of . If it is placed in a container of water (density ), will it sink or float?
Solution:
The object will float.
Explanation:
An object floats if its density is less than the density of the fluid it is placed in. Since , the object is buoyant.