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CHEM 121 UNR FINAL EXAM QUESTIONS AND
ANSWERS 2025
Homogenous Mixture - .....ANSWER ...✔✔ mixture
same throughout EX) Air
Heterogenous Mixture - .....ANSWER ...✔✔ Mixture
different throughout EX) Smoke
Density= - .....ANSWER ...✔✔ Mass(g)/Volume(l)
Filtration - .....ANSWER ...✔✔ Used to sperate a
hetro mixture
Distillation - .....ANSWER ...✔✔ from Homo Mixture,
Use boiling points
Kilo - .....ANSWER ...✔✔ 1x10^3
Centi - .....ANSWER ...✔✔ 1x10^-2
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Mili - .....ANSWER ...✔✔ 1x10^-3
Micro - .....ANSWER ...✔✔ 1x10^-6
Nano - .....ANSWER ...✔✔ 1x10^9
Pico - .....ANSWER ...✔✔ 1x10^-12
Add or Subtract = - .....ANSWER ...✔✔ number of
decimal places
multiply or divide = - .....ANSWER ...✔✔ number of
sig figs
Never a sig fig - .....ANSWER ...✔✔ 0's at the
beginning of a number
0's between 2 sig fig - .....ANSWER ...✔✔ Are
significant
all non zero - .....ANSWER ...✔✔ are significant
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0's at the end, when decimal place is present -
.....ANSWER ...✔✔ are significant
Law of conservation of mass - .....ANSWER ...✔✔
matter cannot be created or destroyed
law of constant composition - .....ANSWER ...✔✔
relative proportions of mass are the same
Ernest Ruthford's Experiment - .....ANSWER ...✔✔ shot
particles at a relevance: discovered positively charged
particles, the Nucleus
Atomic Number - .....ANSWER ...✔✔ Top number on
Element, Number of Protons
Number Below Element Symbol - .....ANSWER ...✔✔
Atomic Weight
Isotope - .....ANSWER ...✔✔ same number of protons
different number or neutrons
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Ion - .....ANSWER ...✔✔ same number of protons
different number of electrons
Group 1 - .....ANSWER ...✔✔ alkaline metals
group 2 - .....ANSWER ...✔✔ alkali earth metals
group 16 - .....ANSWER ...✔✔ chalogens
group 17 - .....ANSWER ...✔✔ halogens
group 18 - .....ANSWER ...✔✔ noble gases
groups 3-15 - .....ANSWER ...✔✔ transfer metals
Fractional Abundance - .....ANSWER ...✔✔ [(atomic
weight)(% decimal from)] + [""]
common ions - .....ANSWER ...✔✔ NO3-
SO4-
ClO4-
CHEM 121 UNR FINAL EXAM QUESTIONS AND
ANSWERS 2025
Homogenous Mixture - .....ANSWER ...✔✔ mixture
same throughout EX) Air
Heterogenous Mixture - .....ANSWER ...✔✔ Mixture
different throughout EX) Smoke
Density= - .....ANSWER ...✔✔ Mass(g)/Volume(l)
Filtration - .....ANSWER ...✔✔ Used to sperate a
hetro mixture
Distillation - .....ANSWER ...✔✔ from Homo Mixture,
Use boiling points
Kilo - .....ANSWER ...✔✔ 1x10^3
Centi - .....ANSWER ...✔✔ 1x10^-2
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Mili - .....ANSWER ...✔✔ 1x10^-3
Micro - .....ANSWER ...✔✔ 1x10^-6
Nano - .....ANSWER ...✔✔ 1x10^9
Pico - .....ANSWER ...✔✔ 1x10^-12
Add or Subtract = - .....ANSWER ...✔✔ number of
decimal places
multiply or divide = - .....ANSWER ...✔✔ number of
sig figs
Never a sig fig - .....ANSWER ...✔✔ 0's at the
beginning of a number
0's between 2 sig fig - .....ANSWER ...✔✔ Are
significant
all non zero - .....ANSWER ...✔✔ are significant
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0's at the end, when decimal place is present -
.....ANSWER ...✔✔ are significant
Law of conservation of mass - .....ANSWER ...✔✔
matter cannot be created or destroyed
law of constant composition - .....ANSWER ...✔✔
relative proportions of mass are the same
Ernest Ruthford's Experiment - .....ANSWER ...✔✔ shot
particles at a relevance: discovered positively charged
particles, the Nucleus
Atomic Number - .....ANSWER ...✔✔ Top number on
Element, Number of Protons
Number Below Element Symbol - .....ANSWER ...✔✔
Atomic Weight
Isotope - .....ANSWER ...✔✔ same number of protons
different number or neutrons
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Ion - .....ANSWER ...✔✔ same number of protons
different number of electrons
Group 1 - .....ANSWER ...✔✔ alkaline metals
group 2 - .....ANSWER ...✔✔ alkali earth metals
group 16 - .....ANSWER ...✔✔ chalogens
group 17 - .....ANSWER ...✔✔ halogens
group 18 - .....ANSWER ...✔✔ noble gases
groups 3-15 - .....ANSWER ...✔✔ transfer metals
Fractional Abundance - .....ANSWER ...✔✔ [(atomic
weight)(% decimal from)] + [""]
common ions - .....ANSWER ...✔✔ NO3-
SO4-
ClO4-
