chem semester 1 final

Compounds must have at least ____ kinds of atoms.

two

Is an element a pure substance?

Yes

Is a compound a pure substance?

Yes

Do homogenous mixtures have variable composition?

No

A pure substance has _____ properties and a composition that does not ____.

unique, vary

A compound is a substance which can be ______ because it is made up of more than one element.

decomposed into simpler substances

Groups of atoms are called……

molecules

The Law of Constant Composition states that ______.

compounds have a definite composition, and the relative number of atoms of each element in the compound in the same in every sample.

A homogenous mixture is also called a ______.

solution

Is color a physical or chemical property?

physical

Is melting/boiling point a physical or chemical property?

physical

Is flammability a physical or chemical property?

chemical

Density, hardness and odor are all examples of _____ properties.

physical

Physical properties can be observed ________.

With out changing the substance into another substance

Chemical properties can only be observed ____.

When the substance has undergone a chemical reaction

Toxicity, Reactivity, and corrosion are all examples of _____ properties.

chemical

Intensive properties are independent of _________.

the amount of the substance that is present.

Is density an intensive or extensive property ?

intensive

Extensive properties are dependent on _____.

the amount of mass in a sample

Is boiling point an extensive or intensive property?

Intensive

Is mass an extensive or intensive property?

Extensive

Physical changes are changes in matter that
_________.

do not change the composition of a substance

• Chemical changes result in_________. and
decomposition.

new substances.

Is melting a physical or chemical change?

physical

Is oxidation a physical or chemical change?

chemical change

Filtration process

solid substances are separated from liquids and solutions via a filter

Distillation uses __________.

differences in the boiling points of substances to separate a homogeneous mixture into its components.

Energy is______.

the capacity to do
work or transfer heat

Work is __________.

the energy transferred
when a force exerted on an
object causes a displacement of
that object.

Heat is ________.

the energy used to cause
the temperature of an object to
increase.

Kinetic energy is the energy of _____.

motion…

Potential energy of an object depends on…..

its relative
position compared to other objects.

The magnitude of KInetic energy depends on_______.

on the object’s mass and its velocity

Precision is the measurement of _________.

how close one’s measurements are to eachother

Accuracy refers to

how closely individual measurements agree with correct/ true value

When examining significant figures, all _______ are significant.

nonzero

When examining significant figures, all zeros that are ______ or ______ are significant.

between two nonzeros or at the end of a number containing a decimal point

Chromatography process

a substance is dissolved into its component parts, and then separated by density

Chemical energy is released when bonds are _____.

formed

Chemical energy is absorbed when bonds are________.

broken

The chemical energy of a fuel is due to the ______ stored in the arrangements of its atoms.

potential energy

Law of Conservation of Mass states that __________.

The total mass of substances present at the end of a chemical process is the same as the mass of
substances present before.

Who discovered the Law of Conservation of Mass?

Discovered by Antoine Lavoisier.

Law of Multiple Proportions states that ______________.

If two elements, A and B, form more than one
compound, the masses of B that combine with a given
mass of A are in the ratio of small whole numbers.

What are the four postulates of Dalton’s Atomic Theory?

1. Each element is composed of extremely small, indivisible particles called atoms.

2. All atoms of a given element are identical, but the atom of one element is different to the atoms of other elements.

3. Atoms of one element can not be changed into atoms of a different element.

4. Compounds are formed when atoms of more than element.

Which postulates of Dalton’s theory were wrong?

atoms are indivisible and that all atoms of a given element are identical in mass and properties. 

What 2 things did Cathode Ray discover?

the electron, and its mass to charge ratio

How do Cathode rays work?

by pumpking a container mostly empty, then placing a cathode and anode at each side.. voltage accelerated valence electrons from one side to a ray, proving their existence

What did the gold-foil experiment prove?

the existence of the nucleus

How did the gold foil experiment work?

alpha particles were run through a piece of gold foil, and some were observed to be refracted, meaning a large positive center must be in every atom

The atomic number shows the number of ______ in an atom.

protons

The number of electrons will be equivalent to the number of ______ in any neutral atom.

protons

True or False: Electrons have significant mass.

False: Mass is incredibly tiny and insubstantial to the atomic mass of an element.

What is the difference between an element’s atomic weight and mass number?

Atomic weight is the number on the period table, and it is found by averaging all the natural-found isotopes of an element. The atomic weight is specific to s specific isotope, and is simply the addition of its neutral plus its protons.

How do you find mass number?

add the number of neutrons plus the number of proton specific to an isotope.

What is the formula for atomic weight?

Atomic weight is equivalent to the (all isotopes’ masses) x (all isotopes’ fractional abundance)

What did Millikan’s oil drop experiment prove?

it proved the fundamental unit of electrical charge

What is Group 1 of the periodic table called?

Alkali metals

What is Group 2 of the periodic table called?

alkaline earth metals

What is Group 17 of the periodic table called?

halogens

What is Group 18 of the periodic table called?

noble gases

Ionic compounds are made of up________.

cations and anions

Ionic compounds are generally _____ bonded with ________.

metals, nonmetals

Radioactivity is _________.

the spontaneous emission of a high energy radiation by an atom.

What is Group 6 of the periodic table called?

Chalcogens

What is Group 1 of the periodic table properties?

soft, silvery metals with low densities, low melting/boiling points, and excellent conductivity

What is Group 2 of the periodic table properties?

Softer than transition metals but harder than Group 1 metals due to stronger metallic bonding from two valence electrons

What are the transition metal properties?

hard, dense solids with high melting/boiling points, excellent electrical/thermal conductivity, and a shiny luster, exhibiting malleability and ductility

What is Group 17 of the periodic table properties?

highly reactive nonmetals characterized by seven valence electrons

What is Group 18 of the periodic table properties?

colorless, odorless, monatomic gases known for their extreme chemical inertness due to full valence electron shells, very low melting/boiling points, and weak intermolecular forces

Which periodic group is the most reactive ?

alkali metals (group 1 ) and halogens (group 17) !!!

Which periodic group is the least reactive ?

group 18

What are the properties of group 16?

known as the "oxygen family," characterized by six valence electrons, strong tendencies to form -2 ions

What are the seven diatomic molecules?

H, O, F , Br, I, N, CL

Empirical formulas give…..

the lowest whole-number
ratio of atoms of each element in a compound.

Molecular formulas give….

the exact number of atoms of each element in a compound.

If you have the empirical formula, and you wish to find the molecular formula, what more information do you need?

the molar mass of the molecule

If you have the molecular formula, and you wish to find the empirical formula, how do you do that?

Take out the greatest common divisor of all subscripts

Cations are formed when _________.

at least one electron is lost.

Anions are formed when ______.

at least one electron is gained

In ionic compounds, which element commonly loses an electron ?

the metal

In ionic compounds, which element commonly gains an electron ?

the nonmetal

What are the three types of hydrocarbons?

alkanes, alkenes, alkynes

For oxidation numbers, any lone, neutral element has an oxidation number of :

0

For oxidation numbers, any monatomic ion has an oxidation number of that is equivalent to ________.

the charge of the monoatomic ion

The oxidation numbers of a neutral compound must add up ________.

0

The oxidation number of a polyatomic ion is equivalent to _______.

the charge of the ion

The oxidation number of a group 1 metal will be ______.

1+

The oxidation number of a group 2 metal will be ______.

2+

The oxidation number of a group 17 metal will be ______.

usually 1-

The oxidation number of hydrogen will usually be ______.

1+

The oxidation number of oxygen will usually be ______.

-2

If an element is oxidized, it _______ electrons.

loses

If an element is reduced, it _______ electrons.

gains

If a hydrocarbon has a single bond, it is called an:

alkane

If a hydrocarbon has a double bond, it is called an:

alkene

If a hydrocarbon has a triple bond, it is called an:

alkyne

An hydrocarbon with 1 carbon has the prefix:

meth

An hydrocarbon with 2 carbons has the prefix:

eth

An hydrocarbon with 3 carbons has the prefix:

prop