Cov Lus Nug Piv Txwv Sib Tham Txog Stoichiometry: Nkag Siab Txog Cov Ntsiab Lus Tseem Ceeb thiab Nws Cov Kev Siv
Stoichiometry yog ib ceg ntawm chemistry uas kawm txog qhov sib piv ntawm cov tshuaj reactants thiab cov khoom hauv cov tshuaj lom neeg. Qhov tseem ceeb, stoichiometry muaj feem cuam tshuam nrog txoj cai ntawm kev txuag pawg, thawj zaug tau hais los ntawm Antoine Lavoisier. Kev tshawb fawb no yog lub hauv paus rau ntau lub tswv yim hauv chemistry, los ntawm cov tshuaj yooj yim mus rau cov txheej txheem kev lag luam nyuaj. Tsab xov xwm no yuav tham txog ntau qhov piv txwv ntawm cov teeb meem stoichiometry, nrog rau lawv cov lus piav qhia thiab cov kev daws teeb meem.
Piv txwv 1: Kev sib xyaw ntawm Hydrogen thiab Oxygen
Lus Nug: Xam tus naj npawb ntawm cov dej molecules tsim los ntawm cov tshuaj tiv thaiv ntawm 4 grams ntawm hydrogen (H₂) thiab 32 grams ntawm oxygen (O₂).
Kev Sib Tham:
1. Sau Cov Qauv Kev Sib Tshuam:
Qhov kev sib xyaw ntawm hydrogen thiab oxygen los ua dej tuaj yeem sau ua raws li nram no:
\[ 2H₂ + O₂ \rightarrow 2H₂O \]
2. Xam Qhov Loj Molar:
Lub molar mass ntawm hydrogen (H₂) yog 2 g/mol thiab lub molar mass ntawm oxygen (O₂) yog 32 g/mol. Dej (H₂O) muaj molar mass ntawm 18 g/mol.
3. Xam Tus Naj Npawb ntawm Moles ntawm Reactants:
Tus naj npawb ntawm moles ntawm hydrogen:
\[ \text{mol H₂} = \frac{\text{mass}}{\text{molar mass}} = \frac{4}{2} = 2 \text{ mol} \]
Tus naj npawb ntawm moles ntawm oxygen:
\[ \text{mol O₂} = \frac{\text{mass}}{\text{molar mass}} = \frac{32}{32} = 1 \text{ mol} \]
4. Txheeb xyuas tus neeg sawv cev txwv:
Raws li qhov sib npaug ntawm cov tshuaj tiv thaiv, 2 moles ntawm H₂ cuam tshuam nrog 1 mole ntawm O₂. Ntawm no, hydrogen (2 moles) phim 1 mole ntawm oxygen, raws li stoichiometry ntawm qhov sib npaug.
5. Xam Tus Naj Npawb ntawm Cov Khoom:
Los ntawm cov qauv tshuaj tiv thaiv, 2 moles ntawm H₂ tsim tau 2 moles ntawm H₂O. Vim tias peb muaj 2 moles ntawm H₂, nws yuav tsim:
\[ 2 \text{ moles H₂O} = 2 \times 6,022 \times 10^{23} \text{ molecules} = 1,2044 \times 10^{24} \text{ molecules} \]
Piv txwv lus nug 2: Kev hlawv roj propane
Lo lus nug: Yog tias 44 grams ntawm propane (C₃H₈) raug hlawv tag nrho, cov pa roj carbon dioxide (CO₂) ntau npaum li cas raug tsim tawm ntawm STP?
Kev Sib Tham:
1. Sau Cov Qauv Kev Sib Tshuam:
Qhov kev sib xyaw ua ke zoo tshaj plaws ntawm propane yog:
\[ C₃H₈ + 5O₂ \rightarrow 3CO₂ + 4H₂O \]
2. Xam Qhov Loj Molar:
Lub molar mass ntawm propane (C₃H₈) yog 44 g/mol. Yog li ntawd, tus naj npawb ntawm moles ntawm propane yog:
\[ \text{mol C₃H₈} = \frac{44}{44} = 1 \text{ mol} \]
3. Saib Cov Kev Sib Piv ntawm Stoichiometric:
Los ntawm cov qauv tshuaj lom neeg, 1 mol ntawm C₃H₈ tsim tau 3 mol ntawm CO₂.
4. Xam Qhov Ntim CO₂:
Ntawm STP (tus qauv kub thiab siab), 1 mole ntawm cov roj muaj qhov ntim ntawm 22,4 L. Yog li qhov ntim ntawm CO₂ tsim tawm yog:
\[ \text{Ntim CO₂} = 3 \text{ mol} \times 22,4 \text{ L/mol} = 67,2 \text{ L} \]
Piv txwv lus nug 3: Kev tshuaj xyuas Acid-Base Titration
Lus Nug: Yuav tsum muaj pes tsawg lub kua 0,1 M NaOH kom tsis txhob muaj 50 mL ntawm 0,1 M HCl kua?
Kev Sib Tham:
1. Sau Cov Qauv Kev Sib Tshuam:
Cov tshuaj tiv thaiv ntawm NaOH thiab HCl yog:
\[ NaOH + HCl \rightarrow NaCl + H₂O \]
2. Xam Tus Naj Npawb ntawm Moles ntawm HCl:
\[ \text{mol HCl} = M \times V = 0,1 \text{ M} \times 0,050 \text{ L} = 0,005 \text{ mol} \]
3. Xam Tus Naj Npawb ntawm Moles ntawm NaOH:
Los ntawm cov qauv tshuaj tiv thaiv, 1 mole ntawm NaOH cuam tshuam nrog 1 mole ntawm HCl. Yog li ntawd, cov moles ntawm NaOH uas xav tau kuj yog 0,005 moles.
4. Xam Qhov Ntim ntawm NaOH:
\[ \text{Volume ntawm NaOH} = \frac{\text{mol}}{M} = \frac{0,005 \text{ mol}}{0,1 \text{ M}} = 0,050 \text{ L} = 50 \text{ mL} \]
Piv txwv lus nug 4: Kev tshuaj tiv thaiv nrog cov tshuaj reagent tso tawm
Lus Nug: Yog tias 10 grams ntawm calcium carbonate (CaCO₃) raug tshuaj nrog 100 mL ntawm 1 M HCl kua, muaj pes tsawg grams ntawm carbon dioxide (CO₂) raug tsim tawm?
Kev Sib Tham:
1. Sau Cov Qauv Kev Sib Tshuam:
Qhov kev sib xyaw ntawm CaCO₃ thiab HCl yog:
\[ CaCO₃ + 2HCl \rightarrow CaCl₂ + H₂O + CO₂ \]
2. Xam Qhov Loj Molar:
Qhov hnyav ntawm CaCO₃ yog 100 g / mol, thiab HCl yog 36,5 g / mol.
3. Xam Tus Naj Npawb ntawm Moles ntawm Reactants:
\[ \text{mol CaCO₃} = \frac{10 g}}{100 g/mol}} = 0,1 mol \]
\[ \text{mol HCl} = 1 \text{ M} \times 0,1 \text{ L} = 0,1 \text{ mol} \]
4. Txheeb xyuas tus neeg sawv cev txwv:
Raws li qhov sib npaug ntawm cov tshuaj tiv thaiv, 1 mol ntawm CaCO₃ cuam tshuam nrog 2 mol ntawm HCl. Ntawm no, CaCO₃ yog cov tshuaj reagent txwv vim tias 0,1 mol ntawm CaCO₃ yuav xav tau 0,2 mol ntawm HCl, thaum peb tsuas muaj 0,1 mol ntawm HCl.
5. Xam Tus Naj Npawb ntawm Cov Khoom:
Nrog 0,1 mol ntawm HCl, tsuas yog 0,05 mol ntawm CaCO₃ yuav ua rau muaj kev cuam tshuam, tsim tawm 0,05 mol ntawm CO₂.
6. Xam Qhov Loj ntawm CO₂:
Lub molar mass ntawm CO₂ yog 44 g/mol. Yog li ntawd, lub mass ntawm CO₂ uas tsim tawm yog:
\[ \text{qhov hnyav ntawm CO₂} = 0,05 \text{ mol} \times 44 \text{ g/mol} = 2,2 \text{ g} \]
Xaus
Kev nkag siab txog stoichiometry xav tau kev paub txog molar mass, cov tshuaj lom neeg cov tshuaj tiv thaiv, thiab lub tswv yim ntawm moles. Kev xyaum nrog ntau yam teeb meem piv txwv tuaj yeem pab txhawb kev nkag siab txog kev sib raug zoo ntawm cov reactants thiab cov khoom hauv cov tshuaj tiv thaiv. Tsab xov xwm no nthuav qhia ntau yam teeb meem piv txwv uas npog ntau hom kev tiv thaiv, los ntawm cov yooj yim mus rau cov uas cuam tshuam nrog kev txwv cov reactants, los pab piav qhia lub tswv yim ntawm stoichiometry.
