Exam 1: Chemistry 1230 BGSU

Law of Conservation of Mass

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

Law of Definite Composition

A pure compound has a “constant composition”, meaning the same regardless of source, manner of preparation. A given compound always contains the same proportion of elements by mass.

Law of Multiple Proportions

If two elements A and B form two different compounds, the masses of A that combine with a fixed mass of B are in a small whole number ratio

Daltons theory

-Each element is made up of tiny particles called atoms.

-The atoms of a given element are identical, the atoms of different elements are different in some fundamental way or ways.

-Chemical compounds are formed when different atoms combine with each other in simple whole number ratios. A given compound always has the same relative numbers and types of atoms.

-Chemical reactions involve reorganization of the atoms, changes in the way they are bound together. The atoms themselves are not changed in a chemical reaction.

Newtons second law states?

Force= Mass x Acceleration

Newton formula

1N = 1kg x 1m/s²

Gravitational force formula

F= m x g (f is force, mass is m, g is gravity)

Electrostatic force law formula

F = 1/4pie0 q1q2/d²

Coulombs Law Formula

F = 1/4pie0 q1q2/d²

Current formula

c/s (c is charge in coulomb, s is time in seconds)

Magnetic force formula

F=qvB (v perpendicular to B and F perpendicular to both)

For Coulombs law, if d² is decreased by 1/3 then the distance….

increased by a factor of 9

For Coulombs law, if d² is doubled then the distance….

increases by 1/4

The atomic mass unit (amu) is defined as:

one twelfth the mass of a 12^carbon atom

How do you write an isotope?

atomic mass over atomic number and symbol to the right

A row of the periodic table is called a?

period

A column of the periodic table is called a?

group or a family

How do you know if its an ionic compound? by looking at a formula

metal and non metal combination

How to know if it is an molecular compound? by looking at a formula

-covalent bonding (two atoms share one or more pairs of electrons)

Give an example of a halogen

Cl (chlorine)

Give an example of a alkaline metal

Li (Lithium)

Give an example of an alkaline earth metal

Ca (calcium)

Give an example of a inert gas

O (oxygen)

Atomic number means what

number of protons

Atomic mass - Atomic number means?

number of neutrons

electrons and protons are equal if..

it is neutral

atomic mass =

number of neutrons and protons

If there is a anion what does it mean?

more electrons

if there is a cation what does it mean?

less electrons

What are the groups and their names

-1 Alkaline metals

-2 Alkaline earth metals

-transition metals

-metalloids (on staircase except Al)

-7 Halogens

-8 Inert gas (noble gas)

Coulomb is a unit of what?

charge, C

Close to an integer of number of amu, but usually note quite (choices: mass number, isotopic mass, atomic mass)

Isotopic mass

A weighted average, weighted by relative natural abundances of isotopes (choices: mass number, isotopic mass, atomic mass)

Atomic mass

Always an integer (choices: mass number, isotopic mass, atomic mass)

Mass number

Listed on periodic table (choices: mass number, isotopic mass, atomic mass)

Atomic mass

Equal to number of protons plus the number of neutrons in nucleus (choices: mass number, isotopic mass, atomic mass)

Mass number

Is often not even close to an integar (choices: mass number, isotopic mass, atomic mass)

Isotopic mass and atomic mass

Based on the data Thomson collected in his experiments using cathode rays, the concept of atomic structure was modified.  Which of the following statements about the atomic structure were validated by his cathode ray experiments?

Cathode rays have mass.

Particles of the cathode rays are fundamental to all matter.

There are subatomic size particles in an atom.

Matter contains negative charge and by inference positive charge.

Based on the data gathered in Millikan's oil-drop experiments, the concept of atomic structure was modified. Which of the following aspects of the structure of the atom was validated by these experiments?

-charge of an electron

-mass of an electron

Based on the data gathered in the Rutherford's scattering experiments, the concept of atomic structure was modified.  Which of the following aspects of the structure of the atom were validated by these experiments?

the nuclear density being large

most of the atomic volume being empty space

the existence of the atomic nucleus

the charge on the nucleus being positive

Identify the equipment that Thomson utilized to do his research.

cathode ray tube

A student re-creates the Millikan oil drop experiment and tabulates the relative charges of the oil drops in terms of a constant, α.

Drop#1	α
Drop#2	3/2α
Drop#3	5/2α
Drop#4	3α

You may want to reference (Page) Section 2.4 while completing this problem.

What charge for the electron (in terms of α) is consistent with this data?

½ α

To analyze the experiment used to determine the properties of an electron.

In 1909, Robert Millikan performed an experiment involving tiny, charged drops of oil. The drops were charged because they had picked up extra electrons. Millikan was able to measure the charge on each drop in coulombs. Here is an example of what his data may have looked like.

Drop	Charge (C)
A	3.20×10−19
B	4.80×10−19
C	8.00×10−19
D	9.60×10−19

Why did different drops have different charges?

because some drops had picked up more electrons than others

Rutherford’s experiment and choose which of the following conclusions are correct.

The atom contains a positively charged nucleus.

The mass of an atom is concentrated at the nucleus.

The majority of the space inside the atom is empty space.

Positive charge is condensed in one location within the atom.

On the basis of Rutherford’s experimental observations, which of the following statements describes the structure of the atom according to Rutherford's atomic model?

In an atom, the positive charges are located in a small core within the atom called the nucleus.

In an atom, negatively charged electrons are dispersed in the space surrounding the positively charged nucleus of an atom.

Identify the equipment that Millikan utilized to do his research.

oil atomizer, light source, microscope

Rutherford proposed the

nuclear theory