2024-05-28T08:24:53+03:00[Europe/Moscow] en true <p>define relative atomic mass</p>, <p>define isotopic mass</p>, <p>define molecular mass</p>, <p>define formula mass</p>, <p>define mole</p>, <p>calculate A<sub>r</sub> of element given relative abundances of isotopes</p>, <p>define empirical formula</p>, <p>define molecular formula</p>, <p>calculate empirical formula by combustion data</p>, <p>calculate empirical formula by using volume of gases in combustion reactions</p>, <p>determine percentage yield of product</p>, <p>how to balance redox equations</p>, <p>how to calculate new oxidation no. of element</p> flashcards
H2 Chemistry 2 - Mole calculation

H2 Chemistry 2 - Mole calculation

Customize
collection saved
Share
Long Term Learning Spaced Repetition
Add to Long Term Learning Desk
Fast learning Repeat this set of flashcards
Preview Test Spell
Play
Match
Review

  • define relative atomic mass

    Ar, ratio of weighted average mass of 1 element atom:1/12 mass of 12C atom

  • define isotopic mass

    ratio of mass of 1 element isotope atom:1/12 mass of 12C atom

  • define molecular mass

    (Mr)of covalent compound; ratio of weighted average mass of 1 substance molecule:1/12 mass of 12C atom

  • define formula mass

    (Mr)of ionic compound; ratio of weighted average mass of 1 formula unit:1/12 mass of 12C atom

  • define mole

    unit of measurement, measures amount of substance in given mass/volume >

    1 mole of substance = amount of substance containing 6x1023(Avogadro's constant) particles

  • calculate Ar of element given relative abundances of isotopes

    Sum of (% of isotope x isotope mass) = weighted average

  • define empirical formula

    formula showing simplest whole no. ratio of atoms of diff elements in compound

  • define molecular formula

    formula showing actual no. of atoms of diff elements in 1 molecule of compound

  • calculate empirical formula by combustion data

    hydrocarbon combustion general equation

    CxHy(g) + (x+y/4)O2(g) -> xCO2(g) + (y/2)H2O(l)

    given organic compound mass, CO2,H2O mass,

    all C converted to CO2, all H converted to H2O;

    calculate nCO2 to get nC, then mass of C >

    calculate nH2O to get nH, then mass of H >

    calculate simplest mole ratio

  • calculate empirical formula by using volume of gases in combustion reactions

    hydrocarbon combustion general equation

    CxHy(g) + (x+y/4)O2(g) -> xCO2(g) + (y/2)H2O(l)

    volume ratio=mole ratio,

    all hydrocarbons burn in excess O2, give H2O, CO2 as only pdt;

    after complete combustion,

    1st contraction in gases vol when mixture cooled to rtp >

    2nd contraction in gases vol when mixture passed thru base, acidic CO2 reacted away >

    1st contraction = total initial vol - total final vol = V(CxHy) + V(O2 reacted) - V(CO2)

    2nd contraction = V(CO2)

  • determine percentage yield of product

    theoretical yield; max calculated pdt quantity when all LR reacted

    actual yield; pdt quantity actually obtained during experiment

    % yield = actual yield/theoretical yield x 100%

  • how to balance redox equations

    no. of e- lost from RA = no. of e- gained by OA

    disproportionation rxn; redox rxn, same species simultaneously [R] & [O] >

    KOHe(acidic medium)

    balance Key element

    balance O2 by adding H2O

    balance H by adding H+

    balance total charge by adding e-

    if basic medium, add same no. of OH- as H+, give H2O

  • how to calculate new oxidation no. of element

    when known nA react w/ stoichometric nB, can calculate change in O.S;

    construct half-eqn for A(initial, final O.S known) >

    calculate n(e- lost/gained) using nA; equate amount to n(e- gained/lost) by B >

    determine no. of e- transferred by 1 mole of B using mole ratio >

    determine new oxidation no. of B