CHEM 103 EXAM 2024| ACTUAL EXAM QUESTIONS WITH IN-
DEPTH ANSWERS| EXPERT VERIFIED FOR GUARANTEED
PASS| LATEST UPDATE
what is an extensive property? - CORRECT ANSWER - depends on the amount of substance
(volume, heat, mass)
significant figures - CORRECT ANSWER - non-place holding digits (not marking the decimal
place)
what digits in are significant? - CORRECT ANSWER - interior zeroes, non zeros, trailing zeroes
after a decimal point or before a decimal point while after a nonzero
what digits are not significant? - CORRECT ANSWER - leading zeroes (zeroes to the left of the
first nonzero digit), before an implied decimal point: ambiguous
dimensional analysis - CORRECT ANSWER - information given * conversion factor(s)=
information sought
what is the law of conservation of mass and who created it? - CORRECT ANSWER - matter is
neither created nor destroyed (total mass of substance in a chemical reaction does not change--
>mass of reactants combined=mass of product)
Lavosier created it
what is the law of definite proportions and who created it? - CORRECT ANSWER - all samples
of a given compound, regardless of source, have the same proportions of their constituent
elements
ex: mass ratio
Proust created it
what is the law of multiple proportions and who created it? - CORRECT ANSWER - when two
elements (A and B) form 2 different compounds, masses of element is that combine with 1g of
element A can be expressed in a ration of small whole numbers
,Dalton created it
neutrons - CORRECT ANSWER - neutral particles within nucleous
protons - CORRECT ANSWER - Positively charged particles within nucleous
electron - CORRECT ANSWER - negatively charged particles outside the nucleous
what is the most important number to identify when identifying an element? - CORRECT
ANSWER - the number of protons (DEFINES THE ELEMENT)
in a chemical reaction the number of _______ never changes - CORRECT ANSWER - protons
atomic number - CORRECT ANSWER - number of protons in an atoms nucleous (Z: bottom left
of chemical symbol)
chemical symbol - CORRECT ANSWER - one or two letter abbreviation listed directly below its
atomic number on the periodic table
mass number - CORRECT ANSWER - sum of the number of neutrons and protons (A: top left
of chemical symbol)
What is an isotope? - CORRECT ANSWER - atoms with the same number of protons but
different numbers of neutrons
the reported atomic mass for a given element is a weighted average of masses according to the
_____ ________ of each isotope? - CORRECT ANSWER - natural abundance
what is natural abundance? - CORRECT ANSWER - percent of an element that is a particular
isotope
,each isotope has a mass that can be... - CORRECT ANSWER - calculated as the addition of the
mass of the subatomic particle
what are ions/how are they created? - CORRECT ANSWER - during chemical changes atoms
can gain/lose electrons and become charged ions
cations - CORRECT ANSWER - positively charged ions
anions - CORRECT ANSWER - negatively charged ions
nonmetals - CORRECT ANSWER - upper right side of periodic table (zigzag diagonal line
running from boron to astatine)
varied: some solid, liquid, or gas at Room Temp, poor conductors of heat and electricity, and
gain electrons when undergoing chem changes
ex: Oxygen, Carbon, Sulfur, Bromine, Iodine
metalloids - CORRECT ANSWER - very useful for technology: many atoms that lie along
zigzag diagonal line that divide metals and nonmetals
some are semiconductors because of intermediate electrical conductivity
ex: silicon, arsenic, antimony
metals - CORRECT ANSWER - lie on lower left side and middle of the periodic table
solid at RT, good conductors of heat, malleable, ductile, often shiny, tend to lose electrons
ex: chromium, copper, stronium, gold, lead
main group element properties are _______ while transition elements and metals are ___
________. - CORRECT ANSWER - predictable, not predictable
noble gasses - CORRECT ANSWER - 8A: unreactive (highly stable)
ex: helium, neon, argon, krypton, xenon
alkali metals - CORRECT ANSWER - IA: reactive metals
, ex: sodium, lithium, potassium, rubidium
alkaline earth metals - CORRECT ANSWER - 2A: fairly reactive (not as much as alkali metals)
ex: calcium, stronium, barium, magnesium
halogens - CORRECT ANSWER - 7A: very reactive nonmetals (readily available in nature)
ex: chlorine, bromine, iodine, flourine
alkali metals lose ___ electron - CORRECT ANSWER - 1 (+1 cation)
alkaline earth metals lose __ electrons - CORRECT ANSWER - 2 (2+ cations)
halogens gain __ electron - CORRECT ANSWER - 1 (1- anion)
oxygen fam nonmetals (6A) gain ___ electrons - CORRECT ANSWER - 2 (2+ cations)
main group elements tend to form ions with same number of electrons as nearest _____ ___ -
CORRECT ANSWER - NOBLE GAS
atomic mass - CORRECT ANSWER - average mass for each element ("weighted average")
listed directly beneath symbol and represents average mass of isotopes
what is avagadro's number - CORRECT ANSWER - 6.022 x 10^23 particles
what relationship does the mole give? - CORRECT ANSWER - between the mass and the
number of atoms in an element
molar mass - CORRECT ANSWER - the mass of one mol of atoms of an element
