Final exam review

Hypothesis
An unverified explanation of a natural phenomenon
Scientific Method
The process of making observations, proposing a hypothesis, testing the hypothesis, and developing a theory that explains a natural event
Theory
An explanation of an observation that has been validated by experiments that support a hypothesis
2.20
1 kg = ____ lb
454
1 lb = ____ g
946
_____ mL = 1 qt
1.06
1 L = ____ qt
2.54
_____ cm = 1 in.
39.4
1 m = ____ in.
0.621
1 km = ____ miles

Mass


Volume

 

The formula for Density is
4.184
1 cal = _______ J
TFº= 1.8(TC°) + 32
The formula to change Celsius to Fº is
TK = TC + 273
The formula to change Celsius to Kelvin is

heat cal(or J)


grams x (Change in Temp Cº)

 

Specific Heat (SH) =
mass x ΔT x SH
Heat =
1 kcal or 4.184kJ
1 Cal =
pure substances
A _______ is matter that has a definite composition. There are two kinds: elements and compounds
element
An ______ is the simplest pure substance b/c it is composed of only one kind of material. Ex. Si, Fe, Al
compound
A ______ is also a pure substance, but it consists of two or more elements always in the same proportion.
mixture
In a _______ two or more substances are physically _____, but not chemically combined
homogeneous
In a ________ mixture, also called a solution, the composition is uniform throughout the sample. Ex. air, saltwater
Liquid
Has a definite volume but not a definite shape, particles move in random directions but are sufficiently attracted to each other to matin def. vol. not a rigid structure
Solid
Has a definite shape and volume, strong attractive forces hold particles close together
Gas
Does not have a def. shape or volume. The particles are far apart, have little attraction, move at high speeds, taking shape/vol. of container
Heating Curve
[image]
Cooling Curve
[image]

Group 1 – alkali metals

Group 2 – Alkaline earth metals

Middle Transition elements

Group 7 – Halogens

Group 8 – Noble gases

[image]

Green – Metals

Blue – Metalliods

Yellow – Nonmetals

[image]
Atomic number
Is equal to the number of protons in the nucleus of an atom, is used to identify and define each element
Mass number
number of protons + number of neutrons
Isotopes
are toms of the same element that have diff. number of neutrons
atomic mass
the weighed average of the ______ of all the naturally occuring isotopes of that element
Atomic size
[image]
Ionization Energy
[image]
Half life
of a radioisotope is the time for a radiation level to decrease (decay) to one-half of the original value
Alpha Decay 

     4 He                                          

2

mass number 4 less

atomic number 2 less

shielding: paper, clothing

Beta Decay β

    0 e

-1

Mass # – same

Atomic # – +1

shielding: Heavy clothing, lab coats, gloves

Metal
_____ atoms lose all their valence electrons from their outermost energy level
increases
The size of nonmetal atoms _______ because they gain electrons in the outermost energy level.
Ionic bond
Loss and gain of electrons
Covalent bond
Sharing of electrons
Nonpolar
A covalent bond between atoms with identical or very similar electronegativity values is ________
Polar
Atoms with diff. electronegativity values. When electrons are shared unequally, the bond is _____
dipole

A polar covalent bond that has a separation of charges is called a 

δ+ and δ  , δ+ and δ

Nonpolar

Polar

Ionic

 Shared equally H-H 0 – 0.4 –

Shared unequally H δ+-Br δ 0.5 – 1.7

Electron transfer Na+ Cl – 1.8 +

VSEPR theory

Valence-Shell Electron-Pair Repulsion

indicates that the electron groups will move as far apart as possible to reduce the repulsion between their negative charges
Nonpolar
Molecules with two or more polar bonds can also be ______ if the polar bonds have a symmetrical arrangement in the molecule
polar
In a _______ molecule, one end of the molecule is more negatively charged than another end. Occurs when the polar bonds dont cancel each other
nonpolar
a _______ molecule occurs when the polar bonds or dipoles in a molecule cancel each other 
Strongest to weakest

Arranged from….

Ionic bonds, hydrogen bonds, dipole-dipole attractions, dispersion forces

bottom of the arrow weakest, top of the arrow strongest
[image]
Oxidation
is defined as the loss of electrons
Reduction
defined as the gain of electrons
REDOX
electrons are transferred from one substance to another

oxidized

reduced

In terms of oxidation and reduction atoms of a metal are ________, and atoms of a nonmetal are _______

increases

decreases

losing electrons _______ charge

gaining electrons _______ charge

6.02 x 1023


1 mole

 

Avogadro’s number is______ is used as a conversion between the ;moles of a substance and number of particles it contains

mass


volume

;

Percent concentration is
Soluble
Alkali metals, NH4+1, NO3-1, Cl, Br, I, SO4-2
NOT SOLUBLE

Ag, Pb, Hg,

(Ca, Sr, Br, P)unless + ion is larger

OH-1, CO3-2, S-2, PO4-3;(unless with alkali metals)

x

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