Matter & Chemical Change Flashcards
What are the two types of matter?
- Pure substances
- Mixtures
What type of mixture is Homogeneous? Heterogeneous?
Homogeneous: solutions & colloids
Heterogeneous: mechanical mixtures & suspensions
What are the two types of pure substances?
- an element
- a compound
What is an element?
a pure substance made entirely of one type of atom
What is the basic structure of an atom?
in the center, there is a nucleus that holds protons and neutrons. orbiting the outside, there are electrons
What is a compound?
a pure substance that is made up of one or more atoms
What is a mechanical mixture?
A heterogeneous combination of two or more substance that simply will not mix
Ex: mixed veggies
What is a solution? Will the components separate overtime? Can they be separated by filtration?
homogeneous mixtures of a solute dissolved in a solvent
-they will NOT separate overtime
-can NOT be separated by filtration
Ex: iced tea
What is a suspension? Will the components separate overtime? Can they be separated by filtration?
a heterogeneous mixture in which insoluble particles are suspended in a liquid or gel.
-they WILL separate over time
-the solids CAN be separated by filtration
Ex: orange juice with pulp
what is a colloid? Will the components separate overtime? Can they be separated by filtration?
a homogeneous type of suspension, but solid particles are finer
-they WONT separate overtime
-they WONT separate through filtration
Ex: milk
What is a chemical reaction?
When substances react with each other to form products with different chemical properties
Ex: hydrogen gas reacting with oxygen gas to form liquid water
2 H2(g) + O2(g) —> H2O(l)
what is the definition of properties?
to describe the physical appearance and composition of a substance
what are examples of physical properties?
-boiling point
-ductility (can be turned to wire)
-malleability (can be pounded into a sheet)
-state
-solubility
-conductivity
-color
define chemical properties
to describe the reactivity of a substance
what are examples of chemical properties?
-ability to burn
-odor
-behaviour with air
-behaviour with water
-reaction with acids
-reaction to heat
-reaction to red & blue litmus paper
What are the difference between chemical and physical properties?
physical:
-no new substance produced
-change of location
-changes state only
-may be easily reversed
chemical:
-precipitate produced (solid formed)
-heat or light produced
-gas produced
-new color
-new odor
-not reversible by physical means
what did Aristotle believe?
believed all matter was composed of combinations of fire, earth, air, and water
what did John Dalton believe?
-Billard ball model
-all matter is made up of small particles called atoms
-atoms of different elements have different properties
what did Neils Bohr believe?
electrons travel around the nucleus in discrete levels
what did Democritus believe?
proposed that matter was made of tiny particles called “atomos,” meaning invisible
What did J.J. Thompson believe?
-plum pudding model
-atom was a sphere with a positive charge embedded with negative particles
what did Ernest Rutherford believe?
atom had a tiny positively charged nucleus
what did Nagaoka believe?
electrons outside sphere, like the rings of saturn
