University:
Cornell University
Course:
CHEM 2070 | General Chemistry I
Academic year:

2019
Views:

179

Pages:

8
Author:

belgaeqh

Heat and Tumperature Review DIRECTIONS: Write on the line at the right of each statement the number that makes the statement an equalify when substituted for the corresponding number. �031( 30°c = _ill_K 2. -25•c = -.LK 1. �2 -83 3 '(,, 3. 190K = _fil_ °C 4. 300K=-L·c 5. 6500 cal 27 'l = _fil_ kJ 6. 1.62 kJ = ....Lkcal 1 . J:. le 2-- l I � �\ . �4 4 �1.2.i<:.15 , 3'1 cu,l 6 DIRECTIONS: Write on the line at the right of each statement the letter preceding the word or expression that best completes the statement 7. Determining whether an object feels hot or cold to the touch is a way of measuring its (a} temperature; (b) heat; (c) density; (d) none of the above. 8. The measurement using a thermometer is based on the (a) type of thermometer liquid; (b) quantify of thermometer liquid; (c) unifonn expansion or contraction of the thermometer liquid; (d)_ thermometer liquid's color. 9. Warer freezes at(a) 273.15K; (b) 100°C; (c) OK; (d) 373.15K. 10. The equation used to convert from the Celsius to Kelvin scale is (a) T(K) = i(0C) + 100; (b) T(K) = i(°C) + 273.15; (c) T(C) = i(K) + 100; (d) T(0C) = t(K) + 273.15. 11. If two systems do not have heat flowing between them, they have the same (a) densicy; (b) thermodynamic properties; (c) 5Peclfic heat: (d) temperature. 12. One calorie is the same amount of heat as 4.184 (a) joulei;; (b) Calories; (c) kilojoules; (d) kilocalories. \/ ()., 8 9 10 cl 11 °'= ·- ... .12 DIRECTIONS: Write the answer to questions 13-15 on the line to the right, and show your work in the space provided. 13. ·'A4.0-g sample of iron was heated from o.o•c to 20. •c, and was found to have absorbed 35.2 J of heat. calculate the 5Pecific heat of this piece of iron. 14. Calculate how much heat a copper sample will gain if its specific heat is 0.384 J/(g•C0), its mass is s.oo g, and it is heated from 10.o·c to 40.o•c. i� & 3 (Jt� J/q C) (tlD· fO) 15. Determine the specific heat of a material if a 6 g sample absorbs 50 J as it is heated from 30 °c to sooe. �o:: to le:\ ( �o � ·7D-� -I 2 • I Ip Cl J 14 Thermochemistry Problems and Questions 1. Write a formation reaction showing how each of the compo11nds are made from their elements. I Incl11de energy (kJ) as part of yo11r eq11ation. Use Appendix I) for heats of formation data. (a) C2H50H(I) (ethanol) (b) HN03Caql (nitric acid) 1/i (c)lead(II)nitratesolid H2+ '/z N 2_ + f 02 ➔ 1'b+-ri'lz + 30 2.. (d)NaHC03(s) (baking soda) N(Ji.'r ➔ 1-\ NO 3 (c-'(;\ 'Pb (NO ?> );;,_ Y.2. H,+t+-}o.... ➔ No, H CD3 (S) (>) 2. Using Appendix I) calculate the enthalpy change (if:; --t°IO, �IP ��" ..........., .......". ····--·· ,· (c) Fe203[s) + 3 co(g) ➔ 2 Fees) + 3 G02(g)"'······ 2(0)+ 3f 393,SI }J - l-011- I 1;,, t 3(,110.S3 JJ \ ��=3�iJ L.\.H and q=msL.\.T problems •� substance cyc/ohexane, C8H12, has the following physical properties: S<••HdJ = 1.2 J/g°C ° s(llquld) = 2.8 J/g C S(gaa) = 0.9 J/g°C melting point = 6.0 °C boiling point = 81.0°C 8Hru,1on = 2.4 kJ/moi • S 1'4,(, aH••� = 18.0 kJ/mol f,j, . 0 't c�. Calculate the heat change needed to do the following, and indicate whether the process is e)(othermic or endothermic: I •1nti1 a) melt 1 00g of solid CsH12 at it's melting point. D � } i:� •:��?I {::.:.�\ k�,l /n"l,>l) "l '2 -8L:i C (, H 1 i.. fA, l-R-; -! \L.-J b) boil 100g of liquid C6H 12 at it's boiling point. 2 2.�.LJ_�'.; o l _ 'j \ 8.i/ I fr' 1<0 Imai) c) freeze 25g of liquid CeH12 at its melting point. )··-\1) C .3��i;�4 • . d) condense 50g �f CeH12 vapor at its boiling point . � :- . Sq m ol ( / , � � ::: ••• /t).b2 k O \t.:i / v,1 (,)) 1 '""•,-·· , " -,·~,wcoc, ''""'""'"tm·�,,,.,,""_,,.�,..,�,1',c,-•,,e,,,,.. / -( e) heat 10g of CsH1 2 from 2°c to 5°C. t •:- f) . 1(),;, 11,7.j/q Y\'1$!:,."T r·��-3.� l j .. c� (5 - 2. ·c ') ' heat 20g oTe6'Ff;2"l'rom 2D°C to 5D'C. I) ·::c '° VYt.$ /.:,..:7-- 2 CJ r� . Ci . . , (2 fs � / c7 C ) ( SO lD C ) ,-�:;o·· j· •· · ,) { t 0 /!12 I , i 9 ;,no\ (r,,H:2. 2. Given the following data for H2O Specific heat of liquid: 4.184 J/g°C Specific heat of gas: 2. 0 J/g°C Specific heat of solid: 2 .1 J/g°C normal melting point: o•c normal boiling point: 1 oo•c Heat of fusion: 6.0 kJ/mol Heat of vaporization: 44 kJ/mol Calculate the heat change needed to do the following, and indicate whether the process is exothermic or endothermic: a) melt 1 00g of solid H2O at it's melting point � "'- �;;.ss 1 1Mc.l(0.o r;"33 -�----�-- i ·( l 0()3 !L-J/YY"11il). , b) boil 100g of liquid H2O at it's boiling point. .t ;. .�--:��-�::\. ( -¥ \ V __ _ _ \ ,;; I V'/\6\ ") \ :: 2 �11.,/ · 2 Ii'.- j ('"'",,_ c) freeze 25g of liquid H2O at Its melting point. ··7-�� d) condense 50g of H2o vapor at its boiling point. ti ... , ? •r"f n"o \ (· -''111 F·; ·,;· J\ l'1 I, ,--:-.-· ····-••,··1.·>2". :1. '• () t)i') k.J/ 1'1/10 J e) heat 35g of H2o from 25°C to 85°C. '· \\Cc- ••,,,,, �,,,,,-�,,,�..,..,,,-"""'"""""""-.,-"'"'" t,< .: f) U .,, 0'1 5 .<'...� 3 e:o -r, ( "-\ , t kA J/ f C \ r-;·�·e;·�·e;c�·-'-c :r • 1 heat235g·orF12O-from·025°C·to -5 °C. 1 I 1 !1 ,(> I lo".()2,;' :::: �;, $ ,w, L:>I f·\·, () . Heating and Cooling Cones• Chemistry 'Jubstance cyclohe1i. � te • C.) 0 f-;:i"i7?_ J ' • / What is the total amount of heat lost by oyclohexane 'as it is cooling from 100°C to o•c. (Watch your units!) - -\ .1 I \7 lO \e e,\ �2_1c(:x.)J • 4) -2 .tio �"� - l\ \::'.-� -7. ,blo ••• k'.J C)·"12DJ. +- -· ;7 2.kj r=�- -··"···· '��·"'·�·�:--\· \ �41,7 l ,_j I Questions Now lets look at combustion reactions a little closer. Consider the combustion of three different fuels: . , natural gas, coal, and wood. Natural gas Is primarily methane (CH4); coal is mostly amorphous carbon (C), and wood is mostly cellulose, a polysaccharlde, which we for simplicity will represent as glucose (C6H12O6), a monosaccharide. ()Ji Given the following equations: natural gas: CH4fg) + 2 O21g) coal: Cccoal) + 02{g) ➔ ➔ CO2c9> + 2 H2O{I) + 802.3 kJ CO2(g) + 367.5 kJ Calculate the kilojoules of heat liberated by the combustion of one gram of natural gas, coal, and wood. Consider the following thermochemical reaction fur kerosene: j

Chem Heat and Temperature Solution

Related Documents

Recommended Documents

Description

Related Documents

Free up your schedule!

Take 5 seconds to unlock