Principles of Chemistry I – Flashcards

independent of amount of sample; some can be used to identify substances

 (temp, density, gas pressure, melting point)

mass of a single molecule in atomic mass units (amu) 

 the sum of the atomic masses of each atom in a molecule

Composition- which atoms?

Structure- how are atoms connected?

no fixed volume or shape

confomrs to volume and shape of container

particles far apart and moving rapidly

distinct volume but no shape

assumes shape of portion of container it occupies

particles packe close together and moving rapidly (can be poured)

distinct shape and volume

particles held tightly together with little movement

Matter with distinct properties and constant composition

Can be either

-element

-compound

Combination of 2+ pure substance

Relative amts of components can vary

Each component retains its own properties

homo- composition of same materials (solution)

hetero- composition of different materials

Observe without changing the identity or composition of a substance

(color, density, melting point, boiling point)

Describe the way a substance may change or react to form other substances

(flammability)

1. Substance changes physical appearance but not composition

2. Changes of state are physical changes

(melting ice)

1. Substance is transformed into a different substance

2. Called a chemical reaction

(hydrogen burns in air to form water)

1. All matter consists of tiny indivisible atoms.

2. Atoms of an element are identical, but different from those of other elements.

3. Atoms of one element cannot be converted into those of another element.

4. Compounds result from chemical combinations of different elements; atom ratios are integers.

Total mass of materials present after a chemical reaction is the same as the total mass present before the reaction.

Whether in Ankeny or Anchorage, water contains 11.19% hydrogen and 88.81% oxygen by mass.

1. Nuclear fission does divide atoms.

2. Nuclear transmutations do change atoms of one element into those of another.

3. Atoms of an element are not identical.

4. Nonstoichiometric compounds sometimes appear to have non-integer atom formulas/ratios.

English physicist won nobel prize in 1906.

Worked with Cathode rays.

Measured the charge-to-mass ration of the electron

(1.76x10^8 C/g)

Credited for the discovery of electrons

Independent of the electrode material (different metals create the same results)

Are streams of negatively charged particles (electrons)

American pysicist

"Oil-drop" experiment

Caused oil drops to become charged and observed their behavior in an electric field.  This led to the charge on the electron= 1.602x10^-19 C

Given charge to mass ration he computed electron mass to be 9.1x10^-28 g

1. Evenly distribute mass and positive chare (cookie)

2. Small embedded negative particles (chocolate chips)

 Disproved by Rutherford's Gold-Foil Experiment in 1910

;

New Zealand physicist; Father of nuclear physics

Discovered the nature of radioactivity

Explained the phenomenon of radioactivity (spontaneous emission from uranium compounds)

;Gold-Foil; Experiment

Discovered protons in 1919

Studied angles at which alpha particles were scattered after passing through thin gold foil.

This experiment disproved the plum-pudding model of the atom

Alpha Rays- particles; electrons

Beta rays- particles; protons

Gamma rays- non-particles; nuetrons

a small, very dense, positive nucleus

surrounded by negative electrons

atom diameters:~100-500 pm

nuclei diameters:~10^-2 pm

ratio= 10,000 : 1

Rows= periods

Columns = groups