Chem Chapter 1: Atoms

What is matter made out of?

Particles

Is solid compressible?

No

Is gas compressible

Yes

1 type of atom or molecule

Pure substance

Many different types of particles

Mixture

Mixture uniform throughout?

Homogeneous

Mixture not uniform throughout

Heterogeneous

How can elements be created or destroyed

Through nuclear fission/fusion, not by chemical means

How can compounds be seperated

Through chemical reactions into their pure components

What are the two physical ways to seperate mixtures?

Distillation (boiling) and magnets (metals)

Summarizes past observation and predicts future ones

Law

Model that is trying to explain why?

Theory

Law of definite proportions

Elements in a given compound always occur in fixed proportions (ex: water had 2 hydrogen and 1 oxygen in each molecule)

What is each element composed of

Atoms

Who created the atomic theory

John Dalton: elements are made of atoms, atoms are indestructible, all atoms in an element has same mass and properties to distinguish them from one another, atoms combine in whole numbers to create compounds

How do atoms from compounds

They change the bonds they have

Who discovered the electron?

J.J Thomson

How did J.J Thomson discover the electron?

The cathode ray experiment: he found electrons are negatively charged, low mass

What is the charge of most atoms?

Neutral

Who discovered the exact charge of the electron?

Milikan

How did Milikan discover electrons charge

Through his oil drop experiments, he found it to be -1.60×10^-19 C

What did Rutherford good experiment discover?

The nucleus of atoms, matter is not as uniform as appeared

What part of the atom was missing in Rutherford nucleus theory

Neutrons

Atomic number

Number of protons- property of atom

Isotopes

Elements with same protons diff neutrons

How to find atomic mass

Natural abundance move two decimal places left, multipled by mass

How to find missing natural abundance?

Subtract given percentages from 100

Mass spectrometry

Measuring the masses of Atoms and molecules

What does it mean if an atom is neutral ?

Same number of protons and electrons

Postive ion

Cation- less electrons/lose electrons

Negative ion

Anion-gain electron/more electrons

1 mol

6.022×10²³

How do you find molar mass?

The molar mass in grams is equivalent to the atomic mass in AMU