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1. How is a chemical change different than a physical change?
During a chemical change the chemical identity of the substance is changed. During a physical change the chemical identity remains the same but the state of matter or physical property has changed (such as water changing to ice).
2. Explain how Archimedes proved the King's crown was not solid gold.
Archimedes realized that when an object is submerged in water its volume is equal to the volume of the displaced water. By dividing the mass of object (such as the crown) by its volume, the object's density can be determined. Archimedes compared the density of the crown to that of solid gold and determined that the crown was not solid gold.
3. Explain the difference between a heterogeneous and homogeneous mixture.
Heterogeneous is a sample of matter consisting of more than one phase. Homogeneous is a sample of matter consisting of a single phase.
4. What causes matter to change states?
The temperature determines the state of a substance. When heated enough, a solid changes to a liquid, and a liquid to a gas. These changes of state take places because the molecules, or tiny bits of matter than make up the substance, vibrate faster when the substance is heated (kinetic energy increases). When the molecules vibrate faster, the attractive forces that hold the molecules together are broken. When cooled (this is the process of losing heat), a gas changes to a liquid, and a liquid changes to a solid.
5. What is an element?
An element is a substance made up of just one type of atom. Gold is an element. A solid piece of gold is made only of gold atoms. There are 117 known elements and they are all listed on the periodic table.
6. What are the four states of matter in order of distance between particles?
Solid, Liquid, Gas, and Plasma
7. What are the properties of a plasma?
The particles in a plasma are most similar to those in a gas. The particles are negatively charged free electrons and positively charged ions of an atom. The particles are very far apart and the electrons are fast and freely moving.
8. What are the properties of a liquid?
The particles in a liquid are close together but not as close together as in a solid. There is some order to the particles and they flow together freely.
9. What are the properties of a solid?
The particles in a solid are closely packed together. They are often in an ordered arrangement called a crystal lattice.
10. What are the properties of a gas?
The particles in gases are not in contact with each other and are free to move relative to one another. The spacing between individual particles is very far apart. A gas has no fixed volume or shape. It occupies both the shape and the volume of the container it occupies.