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ACS GEN CHEM 2 EXAM REVIEW EXAM 2024/2025 QUESTIONS WITH COMPLETED & VERIFIED SOLUTIONS.
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ACS GEN CHEM 2 EXAM REVIEW EXAM 2024/2025 QUESTIONS WITH COMPLETED & VERIFIED SOLUTIONS.
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ACS GEN CHEM 2 EXAM REVIEWWhich particle, if lost from the nucleus will not result in a change in the atomic number? - ANS
PROTON - one unit of positive charge
ALPHA PARTICLE - has two units of positive charge
BETA PARTICLE - one unit of negative charge
NEUTRON - has no charge, and will not change the atomic number
an atom of the element of atomic number 84 and mass number 199 emits an alpha particle. the
residual atom after this change has an atomic number of _______ and a mass number of
_______. - ANS when an atom emits an alpha it looses 2 protons and 2 neutrons
So atomic number Z which represents the number of protons is decreased by 2 : here 84-2 =82
and The mass number A which represents number of protons + neutrons is dereassed by 4:
here 199-4= 195
side note: beta particles result in gain of one proton and loss of one neutron, so mass stays the
same and atomic number increases by one
in effecting nuclear changes by bombarding target nuclei with positively charged alpha particles
it is necessary to accelerate these particles to high speed because it is necessary to - ANS
overcome the force of repulsion of the nucleus
a simple method of showing experimentally that a solid substance may be ionic is to show that it
- ANS conducts electricity in when dissolved in water
-unique to ionic compounds
the boiling point of water compared with other members of the series can be explained by: -
ANS hydrogen bonding
-has the highest IMF than the other compounds listed due to h bond. h bonds only happen when
H is bonded to N, O, or F
sodium chloride NaCl crystallizes in a face centered cubic lattice of chloride ions, with smaller
sodium ions occupying holes between Cl ions. how many cl- ions are in contact with and single
Na+ ion - ANS 6
-is a octahedral hole - so coordination number of 6; tetrahedral have coordination number of 4
and simple cubic hole has coordination number of 8
, according to the phase diagram showing the gas, liquid and solid phases of a pure substance
what phase or phases can be present at point x (phase diagram where x lies on boiling point
curve) - ANS liquid and gas
-know where each state lies on diagram
three phases are always in same relative positions with varying slopes. if point lies on the phase
boundary line both phases can occur together
what is the normal melting point of the pure substance Z? - ANS 4 degrees celsius
-where 760 mm Hg the melting point curve ( line between solid and liquid) lies at approximately
at 4 degrees celsius)
if it were to ask boiling point you would see what the temperature was at 760 mm Hg for the
boiling point curve (line between liquid and gas)
which substance meets the requirements: cubic solid, poor electrical conductor in solid state,
good conductor when fused - ANS NaCl
ionic bonding; crystalline structure; low conductivity when solid; high conductivity when fused
MAKE SURE TO KNOW TABLE that summarizes bonds and properties!!
Two pure solids A and B each melt at 87.5 degrees celsius. An unknown pure substance X also
melts at 87.5 C. Melting points are obtained from X with A, X with B, and A with B. The melting
point of each mixture is found to be below 87.5. Which conclusion can be made? - ANS X is
different from both a and b
pure substances are differentiated based on the temperature of melting point. All 3 have the
same melting point. if any of the different samples contained the same substance the mixtures
melting point would have the same melting point. If all 3 melting points are lower than the
original melting point than all 3 substances must be different
The vapor pressure of 4 substances given at 20 degrees celsius. which is correct?
1 - .0012
2 - 18
3 - 175
4 - 442 - ANS the surface tension of 2 should be greater than 3
-substances with lower vapor pressure tend to have relatively higher ∆Hvap, BP, and surface
tension
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