Chem 121 UNR final Questions and Correct Answers/ Latest Update / Already Graded

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Chem 121 UNR final Questions and
Correct Answers/ Latest Update /
Already Graded
Homogenous Mixture


Ans: mixture same throughout EX) Air




Heterogenous Mixture


Ans: Mixture different throughout EX) Smoke




Density=


Ans: Mass(g)/Volume(l)




Filtration


Ans: Used to sperate a hetro mixture




Distillation

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Ans: from Homo Mixture, Use boiling points




Kilo


Ans: 1x10^3




Centi


Ans: 1x10^-2




Mili


Ans: 1x10^-3




Micro


Ans: 1x10^-6




Nano

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Ans: 1x10^9




Pico


Ans: 1x10^-12




Add or Subtract =


Ans: number of decimal places




multiply or divide =


Ans: number of sig figs




Never a sig fig


Ans: 0's at the beginning of a number




0's between 2 sig fig

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Ans: Are significant




all non zero


Ans: are significant




0's at the end, when decimal place is present


Ans: are significant




Law of conservation of mass


Ans: matter cannot be created or destroyed




law of constant composition


Ans: relative proportions of mass are the same




Ernest Ruthford's Experiment