Chemistry Final Exam

AB →(heated) A + B

decomposition

combustion reaction

a substance combines with oxygen, releasing a large amount of energy in the form of light and heat

how to tell if a chemical reaction is occuring (5 things)

1. evolution/formation of a gas
2. formation of a solid
3. release/absorption of heat
4. color change
5. change in pH

9

nona

10

deca

12

dodeca

what does the atomic number represent

the number of protons in an element

what is this called?

nuclear notation/isotope symbol

where is the atomic number located in the isotope symbol/nuclear notation?

the subscript

ex: carbon-12 ; what is this called?

hyphen notation

where is the mass number located in the isotope symbol/nuclear notation?

superscript

what does the mass number represent?

the number of protons and neutrons added together

how do you find the number of neutrons in an element?

mass number - atomic number

isotope

all isotopes of an element have the same number of electrons and protons (atomic number) but different number of neutrons resulting in different mass numbers

in isotopes, what two subatomic particles are the same?

protons and electrons

isotopic mass formula

total mass / # of atoms

percent abundance formula

\# of atoms / total # of atoms x 100

atomic mass formula

AWAM = (rel.abundance of isotope 1 x 100) + (rel.abundance of isotope 2 x 100) + (rel.abundance of isotope 3 x 100)

relative abundance formula

percent abundance / 100

the # of protons can be directly determined from what?

the atomic number (ex: Cu is atomic number 29, so it contains 29 protons in the nucleus)

if an atom is neutral, how can the # of electrons be determined?

same as the # of protons

what does it mean in terms of electrons and protons, when an atom has a positive charge?

there are less electrons, and more protons

each positive charge on an atom or ion represents what? ex: Mg²⁺

there is one less electron than proton (in Mg²⁺ there are 12 protons which means there would only be 10 electrons)

what does it mean in terms of electrons and protons, when an atom has a negative charge?

more electrons than protons

each negative charge on an atom or ion represents what? ex: O²⁻

there is one more electron than proton (in O²⁻, oxygen has 8 protons, but would have 10 electrons)

what are the two most common methods for communicating the # of subatomic particles in an atom?

hyphen notation and nuclear notation

chemical symbol def (ex: NaCl)

form of shorthand notation for naming an element

compound def

substances in which 2 or more elements are chemically combined

chemical formula def

combination of symbols which represent the composition of a compound

fragmentation def

the process of breaking apart a molecule

do like charged particles repel or attract

repel

do oppositely charged particles repel or attract

attract

neutral atom def

\# of protons and electrons are the same

what happens in detection?

ions collide w/ a metal plate. electrons are transferred from the metal to the ion, producing a current and thus a signal to a computer

what happens in deflection?

ions are attracted to the negative side of an electromagnetic field causing separation of the mixture based on mass and charge

what happens in ionization?

electrons are knocked off sample particles to form (mostly) +1 ions

what happens in acceleration?

Ions move through a series of charged plates to form a narrow beam of high speed particles with equal kinetic energy

SIG FIGS - are nonzero #s significant or not significant

significant

SIG FIGS - are 0s between two non zero #s significant or not significant

significant

SIG FIGS - are leading zeros or trailing zeros without a decimal significant or not significant

not significant

SIG FIGS - are zeros at the end of a # that also contains a decimal, significant or not

significant

SIG FIGS - are exact numbers or counting numbers significant or not

not significant

in SIG FIGS, the last digit is always…

estimated

SIG FIGS RULES FOR MATH OPERATIONS - if the digit following the last digit is greater than 5, then…

the last digit should be increased by 1

SIG FIGS RULES FOR MATH OPERATIONS - if the digit following the last digit is less than 5, then…

the last digit should stay the same

SIG FIGS RULES FOR MATH OPERATIONS - if the digit following the last digit is 5 but followed by nonzero digits, then…

the last digit should be increased by 1

SIG FIGS RULES FOR MATH OPERATIONS - if the digit following the last digit is 5 but not followed by nonzero digits and proceeded by an odd digit, then…

the last digit should be increased by 1

SIG FIGS RULES FOR MATH OPERATIONS - if the digit following the last digit is 5 but not followed by nonzero digits and proceeded by an even digit, then…

the last digit should stay the same

when adding or subtracting SIG FIGS, the answer must contain…

same # of digits to the right of the decimal point as there is in the starting measurement with the fewest # of digits to the right of the decimal point (ex: 5.44 + 2.6103 = 8.0503 → 8.05)

when multiplying or dividing SIG FIGS, the answer must contain…

the same # of SIG FIGS as there is in the starting measurement w/ the fewest # of SIG FIGS (ex: 12 x 6.41 = 76.92 → 77)

mass formula

density x volume

a measurement provides what kind of data

quantitative

accuracy indicates…

how close a measurement is to the accepted or true value

precision indicates…

how close together or how repeatable results are

ACCURATE measured values are ____ to the accepted value

close

PRECISE measured values are close to _____

one another but not necessarily close to the accepted value

% error formula

% error = l Experimental value - Accepted Value l / Accepted Value x 100

10⁹

Giga

10⁶

Mega

10³

kilo

10²

hecto

10¹

deca

10⁻¹

deci

10⁻²

centi

10⁻³

milli

10⁻⁶

micro

10⁻⁹

nano

mass of substance

molar mass

moles of substance

avagadro's number

avogadro’s number

6\.022 x 10²³ units

formula mass def

the mass of a SINGLE atom of an element, one unit of a compound, or molecule

formula mass units

amu

molar mass def

the mass of ONE MOLE of a substance (element, compound, or molecule)

molar mass units

g/mol (grams per mole)

mole def

a counting # representing 6.022 x 10²³ particles of anything (ions, atoms, molecules, etc.)

molecular formula def

a formula giving the # of atoms of each of the elements present in one molecule of a specific compound

empirical formula def

a chemical formula showing the simplest ratio of elements in a compound rather than the total # of atoms in a molecule

CONVERTING TO SCIENTIFIC NOTATION - when moving the decimal to the right…

the exponent is negative

CONVERTING TO SCIENTIFIC NOTATION - when moving the decimal to the left…

the exponent is positive

significant figures are measured ____ , plus one estimated digit

precisely

law of definite proportions states…

a compound always contains the same elements in the same proportions, regardless of the amount of the sample, where it was found, or how it was prepared

hydrate def

a pure substance that contains water molecules embedded in its crystal structure

anhydrous

the solid that remains behind water molecules ; “without” water

electromagnetic radiation def

a form of energy that exhibits wave-like behavior as it travles through space

electromagnetic radiation has two types of characteristics

wave-like and particle-like

wave length def

the distance between two corresponding points on adjacent waves

greek symbol for wavelength

λ - lambda

wavelength units of measurement

distance - m, cm, nm, etc.

frequency def

the # of waves cycles per unit of time

calculating wavelength and frequency equation

c = λv

greek symbol for frequency

v - nu

frequency units of measurement

waves/second

electromagnetic spectrum def

an arrangement of all forms of ER based on wavelength, frequency, and energy

photon

a particle of ER having 0 mass and is carrying a quantum of energy (specific amount)

containing a quantum of energy is defined as

the minimum quantity of energy that can be lost or gained by an atom

types of ER

radio, radar, infrared, visible, UV, x-rays, gamma rays

types of ER (longest wavelength to shortest wavelength)

radio, radar, infrared, visible, UV, x-rays, gamma rays

types of ER (highest frequency to lowest frequency)

gamma rays, x-rays, UV, visible, infrared, radar, radio

calculating frequency of a wave

v = wave cycles/time

wavelength and frequency are (inversely proportional or proportional)

inversely proportional