Chemistry Exam: 1st Semester (Chapters 1-3)

chemistry

study of composition, structure, and properties of matter, the processes of matter, the process that matter undergoes, and the energy that accompanies these processes

mass

measure of amount of matter

matter

anything that has mass and takes up space

atom

smallest unit of an element that maintains the chemical identity of that element

element

pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom

extensive properties

ex) volume, amount of energy, mass

depend on amount of matter present

intensive properties

ex) melting point, boiling point, density, conductivity

do not depend on amount of matter present

chemical reaction

change that alters chemical properties

physical reaction

change that does not change properties

mixture

blend or two or more kinds of substance that can be separated

pure substance

fixed composition

homogeneous

uniform in composition

heterogeneous

not uniform throughout

vertical columns

families or groups

horizontal rows

periods

metal properties

malleable, ductile, shiny, excellent conductors

nonmetal properties

brittle, poor conductors, gases at room temp.

metalloid properties

semi-conductors

What is most prevalent about noble gases?

generally nonreactive

solid properties

definite shape and volume

liquid properties

indefinite shape and definite volume

gas properties

indefinite shape and volume

Organic chemistry is the study of _________-containing compounds.

carbon

What is/are the reactant/s?

2H₂+O₂→2H₂O

2H₂ and O₂

What is/are the product/s?

2H₂+O₂→2H₂O

2H₂O

What is the scientific method?

a logical approach to solving problems

quantitative

data that is measurable; obervations based on numbers

qualitative

data that is represented with words, not numbers

SI base unit for length

meter

SI base unit for mass

kilogram

SI base unit for time

second

SI base unit for temperature

kelvin

SI base unit for substance

mole

How is mass different from weight?

Mass is amount of matter;weight is gravitational pull of matter

Volume is___________.

amount of space occupied by an object

How do you calculate density?

D(density)=M(mass)/ V(volume)

accuracy

close to the accepted value

precision

close to other measurements

How do you find percentage error?

%E=A(actual)-T(theoretical)/T(theoretical x100

The law of ___________ states that mass is neither created nor destroyed during ordinary chemical reactions or chemical changes.

conservation of mass

The law of __________ states that a chemical compound contains the same elements in exactly the same proportions of mass regardless of the size of the sample or source of the compound.

definite proportions

The law of __________ states that if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers.

multiple proportions

Dalton's Atomic Theory

1. all matter is composed of extremely small particles called atoms

2. atoms of a given element are identical in size, mass, and other properties; atoms of diff. elements differ in size, mass, and other prop.

3. atoms cannot be subdivided, created, or destroyed

4. atoms of diff. elements combine in simple whole number ratios to form chemical compounds

5. in chem. reactions, atoms are combined, separated, or arranged

orbit

set path that Bohr said electrons travel in

orbital

3rd region in an atom where there is a high probability of finding electrons (modern atomic theory)

Name the scientist who concluded that all cathode rays are composed of identical negatively charged particles(electrons)

Thompson

Name the scientist who measured the charge of electron

Millikan

Thompson proposed the ________ which predicted that negative electrons were spread evenly throughout the positive charge of the rest of the room

Plum Pudding Model

Experiments by ________ and his associates in which a piece of gold foil was bombarded with alpha particles led to the discovery of the ________.

Rutherford; nucleus

Most of the mass in an atom is found in the _____.

nucleus

Most of the volume in an atom is found in ___________.

area surrounding the nucleus

Location and charge: protons

nucleus; ⁺1

Location and charge: neutrons

nucleus; 0

Location and charge: electrons

electron cloud; ⁻1

The atomic number tells you the number of _______ present in each atom of that element.

protons

Isotopes have differing numbers of _________.

neutrons

The atomic number tells you the number of ___________ present in each atom of that element.

protons

Isotopes have differing numbers of _________.

neutrons

The mass number is the total number of ________ and ________ in an atom.

protons; neutrons

_____________ is the weighted average of the atomic masses of the naturally occurring isotopes of an element.

Average atomic mass

How do you calculate average atomic mass?

#( % x 100) + #(% x 100)

What number is associated with moles?

1