CHEMl 103l /l CHEM103l Modulel 3:l
(Latestl 2025/l 2026l Update)l Generall Chemistryl Il W/l Labl |l Questionsl &l Answers|l Gradel A|l 100%l Correctl (Verifiedl Solutions)-l Portagel Learning
Q:l NH4Cll isl beingl dissolvedl inl waterl andl thisl processl isl beingl studiedl inl al styrofoaml coffeel cupl withl al lidl andl thel heatl absorbedl isl measuredl byl meansl ofl al thermometerl immersedl inl thel reactionl mixture.l
Enterl thel correctl thermochemistryl terml tol describel thel iteml listed.
Answer:
1)l endothermicl 2)l Surroundings
Q:l Showl thel calculationl ofl thel amountl ofl heatl involvedl ifl 35.6l gl ofl H2Sl isl reactedl withl excessl O2l tol yieldl sulfurl dioxidel andl waterl byl thel followingl reactionl equation.l Reportl yourl answerl tol 4l significantl figures.l
2l H2Sl (g)l +l 3l O2l (g)l →l 2l SO2l (g)l +l 2l H2Ol (g)l ΔHl =l -l 1124l kJ
Answer:
1)l 1l moll H2Sl =l 34.1l gl ofl H2Sl =l 603.2l KJl
(35.6l gl /l 34.1l g)l *l -603.2l KJl =l (1.0439)l *l (-603.2l KJ)l =l -629.7l
2H2Sl (g)l +l 3l O2l (g)l -->l 2l SO2l (g)l +l 2l H2Ol (g)l 1 / 2
Hl =l -1124l KJl reactionl usesl 35.6l gl ofl H2Sl =l 35.6l /l 34.086l =l 1.044l molel ofl H2Sl
ql =l Hl *l newl molesl /l originall molesl ql =l -1124l KJl *l 1.044l molesl ofl H2Sl /l 2l molel H2Sl =l 586.7l givenl offl
2l H2Sl (g)l +l 3l O2l (g)l →l 2l SO2l (g)l +l 2l H2Ol (g)l ΔHl =l -l 1124l kJl ΔHrxl isl forl 2l molel ofl H2Sl
reactionl usesl 35.6l gl ofl H2Sl =l 35.6/34.086l =l 1.044l molel ofl H2Sl
ql =l ΔHrxl xl newl molesl /l originall molesl ql =l -1124l kJl xl 1.044l molel ofl H2Sl /l 2l molel H2Sl =l 586.7l givenl off
Q:l Showl thel calculationl ofl thel newl volumel ofl al gasl samplel whichl hasl anl originall volumel ofl 660l mll whenl collectedl atl 660l mml andl 38oCl whenl thel pressurel increasesl tol 780l mml andl thel temperaturel increasesl tol 45oC.
Answer:
1)l (P1l *l V1)l /l T1l =l (P2l *l V2)l /l T2l >660l mll /l 1000l =l 0.660l ll =l V1l >660l mml /l 760l =l 0.868l atml =l P1l >780l mml /l 760l =l 1.03l atml =l P2l >38l Cl +l 273l =l 311l Kl =l T1l >45l Cl +l 273l =l 318l Kl =l T2l >(0.868)l *l (0.660)l /l 311l =l (1.03)l *l V2l /l 318l =l Vl =l 0.569l literl
(Pil xl Vi)l /l Til =l (Pfl xl Vfl )l /l Tfl >660l ml/1000l =l 0.660l litersl =l Vil >660l mm/760l =l 0.868l atml =l Pil >780l mm/760l =l 1.03l atml =l Pfl >38oCl +l 273l =l 311oKl =l Til >45oCl +l 273l =l 318oKl =l Tfl
(0.868)l xl (0.660)l /l 311l =l (1.03)l xl Vfl /l (318)l Vf=l 0.569l liter
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