Chapters 1-3 (Exam 1) Flashcards
What is Chemistry?
The study of matter and the change that matter undergoes
Scientific Method steps
Observations, Hypothesis, Experiment, model (theory), Further Experiment
International system of units for
- Length
- Mass
- Time
- Electric Current
- Temp
- Amount of substance
- Lumenis intensity
meter, kilogram, second, ampere, kelvin, mole, candela
Amu is what and how many grams is 1 amu
Atomic mass unit, expresses the masses of atoms. 1 amu is 1.66X10^-24
Tera, Giga, Mega, Kilo . Deci, Centi,Milli, , , Micro, Nano Pico
12, 9 6, 3, -1, -2, -3, -6, -9, -12
density =
mass/volume =
Exact numbers
defined values (12 dozen eggs, 2.54 cm in inches, etc)
Grams to moles, Moles to grams: conversion
Divide by molar mass, multiply by molar mass
Moles to atoms, atoms to moles: conversion
Multiply by Avogadro’s number, Divide by Avogadro’s number
Pure substance
matter that has specific chemical composition and distinct properties such as color, state of matter, and solubility. Such as:
- salt
- iron
- Carbon dioxide
Mixture
combination of two or more substances in which each substance retains its distinct identity. No universal constant like substances, mixtures will be different.
- trail mix
- apple juice
Homogeneous
Uniform throught, cannot destinguish components that make it up.
Heterogeneous
not uniform, such as sand with iron fillings in it.
Can both types of mixtures be seperated?
Yes both can without changing the identities of the individual substances
Physical process
Does not change the identity of a substance. Can go thru phase change
Chemical Process
Changed the substance chemically, cannot be recovered to original form.
Extensive property of matter
Properties dependent on the amount of matter
Intensive property of matter
Properties that do not depend on the amount of matter
What is an atom?
The smallest quantity of matter that still retains the properties of matter
What is an element?
A substance that cannot be broken down into two by any means
Who first proposed atoms?
Democritus, later formalized by John Dalton
What is a cathode ray tube
two metal plates in a glass tube, high voltage source called cathode emits radioactive cathode rays, moves toward positively charged plate, casting a bright light.
- Did not depend on the material from the cathode was made.
- Can be deflected by electric or magnetic fields, repelled by a plate with negative charge and attracted to positive charge.
Who was J. J. Thomson
J. J. Thomson proposed the cathode rays were negatively charged and determined a charge to mass ratio
Who determined the charge of an electron?
R. A. Millikan
Who discovered xrays
William Rontgen
3 types of radioactive rays
Alpha, Beta, and Gamma
Alpha rays
Positive particles that deflect away from positivly charged plate
Beta rays
Electrons, deflect from negative charge plates
Gamma rays
Unaffected by charged plates
Describe the bounce back experiment and who did it
Earnest Rutherford directed alpha particles to thin foils of golf, and most penetrated, but some reflected back.
What is located around the nucleus
Protons and neutrons inside of it and the electrons distributed large distances away
Mass of proton, electron, and neutrons
Proton: 1
electron: 0 (small)
neutron: 1
Charge of proton, electron, neutron
proton: +1.6022 x 10^-19
electron: -1.6022 x 10^-19
neutron: 0
Atomic number and location
Number of protons in an atom of an element
- located on bottom
Mass number
Number of protons+neutrons
- located on top and larger
Isotopes
Atoms that have the same atomic number but different mass numbers. Atomic number may not be present because its the same and should be known
What makes a nucleus stable
If repulsion outweighs attraction, the nucleus disintegrates, emitting particles and/or radiation. If attractive forced prevail, nucleus is stable.
What are the magic numbers and what does it mean?
2, 8, 20, 50, 82, 126.
If the atomic number matches one of them, the atom is more stable.