Ch 3: Matter and Energy Flashcards
What are the three states of matter?
Solid, liquid, and gas
What is a mixture?
A mixture is two or more pure substances combined in variable proportions.
What is the difference between a homogeneous mixture and a heterogenous mixture?
In a heterogenous mixture the composition varies from one region to another. In a homogeneous mixture the composition is the same throughout.
What is an element? A compound?
An element is a substance that cannot be broken down into simpler substances. A compound is a substance composed of two or more elements in fixed definite proportions.
What is the definition of a physical property? What is the definition of a chemical property?
A physical property is one that a substance displays without changing its composition. A chemical property is one that a substance displays only through changing its composition.
Name two subcategories of pure substances
elements and compounds
Name two subcategories of mixtures
homogeneous and heterogeneous
What is a physical change? What is a chemical change?
In a physical change, matter changes its appearance but not its composition. In a chemical change, matter does change its composition.
Solids can be in which two states?
Crystalline, in which its atoms or molecules arrange in geometric patterns with long-range, repeating order (e.g. salt crystals, or diamonds).
Amorphous, in which its atoms or molecules do not have long-range order (e.g. glass, rubber, or plastic).
What is the law of conservation of energy?
Energy is neither created or destroyed.
What is the law of conservation of mass?
Matter is neither created nor destroyed in a chemical reaction.
What is potential energy?
The energy associated with matter’s position or composition.
What is kinetic energy?
The energy associated with matter’s motion
What is an exothermic reaction? Give an example.
Chemical reactions that release energy, like the explosion of TNT.
What is an endothermic reaction? Give an example.
Chemical reactions that absorb energy from their surroundings as they occur, like a cold pack absorbing heat.
