Basics Flashcards
What is matter?
Something with mass and volume
What is Chemistry?
Study of composition, structure, and properties of matter and the changes it undergoes.
What is the law of conservation of mass?
Mass reactants = mass products
Metric?
khdudcm
What is a physical change?
Change a property without changing identity of substance
What is a chemical change?
Changes that change the identity of a substance
What’s an extensive physical change?
Depends on amount of matter. (Length, width, weight, etc)
What’s an intensive physical property?
Does not depend on amount of matter.
What are the four indications of a chemical change?
1) change in color
2) change in energy (hotter, colder, giving off light
3) evolving of a gas (bubbles)
4) formation of a precipitate
What’s an exothermic rxn?
Heat is leaving system (feels hot)
What is an endothermic rxn?
Heat is entering a system (feels cold)
What’s a theory?
Explanation of why (backed by experiments)
What’s a law?
Statement about what’s observed. (Backed by experiments)
What’s the formula for % error?
Vtrue - Vexp
————— * 100
Vtrue
What is a mixture?
A combination of things not chemically combined. (Can be separated physically)
What are some ways to separate mixtures?
Magnetism
Distillation (boiling point)
Filtration (particle size)
Chromatography (affinity)
What’s a heterogeneous mixture?
Can see individual particles
What is a homogeneous mixture?
Can’t see individual particles
What a direct relation? (Math)
One divided by the other gives a constant.
(y = kx)
graphs a straight line
What is an inverse relation? (Math)
One multiplied by the other gives constant
y = k/x
Curved line
What is the law of definite composition?
A chemical compound contains the same elements in exactly the same properties by mass regardless of sample size
What is the law of multiple proportions?
Ratio of masses of elements in a compound is always a ratio of small whole numbers
Who first came up with the idea of an atom?
Democritus
What are Dalton’s 5 points
-All matter is composed of atoms
£All atoms of a given element are identical (size,mass,chem properties). Atoms of a specific element are diff from other elements.
£Atoms can’t be created divided or destroyed
-diff atoms combine in diff whole # ratios to form compounds
-in a chem rxn atoms are separated combined or rearranged
Who performed the Cathode Ray Experiment?
J J Thompson
What are 3 things learned from the cathode ray experiment?
- all substances contain e-
- electrons have mass
- electrons have a negative charge
Who preformed the golden foil experiment?
Rutherford
What are three things learned from the gold foil experiment?
- Nucleus is small (out of total atom)
- nucleus has a positive charge
- nucleus has high mass
Who preformed the oil drop experiment?
Millikan
What did the oil drop experiment teach us?
Electron mass
Other things in atom
What is the approximate mass of an electron?
1/2000 the size of an H atom
What is an isotope?
Atom with differing mass due to differing numbers of neutrons
What is a mass number?
The sum of the neutrons and protons
What is an ion?
A charged species
What are the two kinds of ion?
Cation +
Anion -
