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Experiment No. 12(a)

Heat Combustion of Liquid Hydrocarbon Fuels by omb Calorimeter

Author: Date Performed: 2-9-16

Lim, Darwin B. Date Submitted: 4-13-16

a!a"am, A"fred

!. !ntroduction#he $a"ue of H !an be determined e%&erimenta""' b' mea(urin) the heat f"ow

a!!om&an'in) a rea!tion at !on(tant &re((ure. *hen heat f"ow( into or out of a

(ub(tan!e, the tem&erature of the (ub(tan!e !han)e(. +%&erimenta""', we !andetermine the heat f"ow a((o!iated with a !hemi!a" rea!tion b' mea(urin) the

tem&erature !han)e it &rodu!e(. #he mea(urement of heat f"ow i( calorimetry an

a&&aratu( that mea(ure( heat f"ow i( a calorimeter .

!!. "#eory Heat Capacity and $pecific Heat

*hen an ob e!t (it( in the Sun and ab(orb( heat, it( tem&erature !han)e(. #hetem&erature !han)e e%&erien!ed b' an ob e!t when it ab(orb( a !ertain amount of

ener)' i( determined b' it( heat capacity . *e define the heat !a&a!it' of an ob e!t a(

the amount of heat re uired to rai(e it( tem&erature b' 1 / 0or 1 . #he )reater the

heat !a&a!it' of a bod', the )reater the heat re uired to &rodu!e a )i$en ri(e in

tem&erature. or &ure (ub(tan!e( the heat !a&a!it' i( u(ua""' )i$en for a (&e!ified

amount of the (ub(tan!e. #he heat !a&a!it' of 1 mo" of a (ub(tan!e i( !a""ed it( molar

heat capacity . #he heat !a&a!it' of 1 ) of a (ub(tan!e i( !a""ed it( specific heat

capacity , or mere"' it( specific heat . #he (&e!ifi! heat of a (ub(tan!e !an be

determined e%&erimenta""' b' mea(urin) the tem&erature !han)e, T , that a 5nown

ma((, m, of the (ub(tan!e under)oe( when it )ain( or "o(e( a (&e!ifi! uantit' of heat,

q:

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omb Calorimeter

ne of the mo(t im&ortant t'&e( of rea!tion( (tudied u(in) !a"orimetr' i( !ombu(tion. A

!om&ound, u(ua""' an or)ani! !om&ound, i( a""owed to rea!t !om&"ete"' with e%!e(( o%')en.

ombu(tion rea!tion( are mo(t !on$enient"' (tudied u(in) a bomb calorimeter , a de$i!e (hown(!hemati!a""' in i)ure 1. #he (ub(tan!e to be (tudied i( &"a!ed in a (ma"" !u& within a (ea"ed

$e((e" !a""ed a bomb . #he bomb, whi!h i( de(i)ned to with(tand hi)h &re((ure(, ha( an in"et

$a"$e for addin) o%')en and a"(o ha( e"e!tri!a" !onta!t( to initiate the !ombu(tion. After the

(am&"e ha( been &"a!ed in the bomb, the bomb i( (ea"ed and &re((uri7ed with o%')en. 8t i( then

&"a!ed in the !a"orimeter, whi!h i( e((entia""' an in(u"ated !ontainer, and !o$ered with an

a!!urate"' mea(ured uantit' of water. *hen a"" the !om&onent( within the !a"orimeter ha$e

!ome to the (ame tem&erature, the !ombu(tion rea!tion i( initiated b' &a((in) an e"e!tri!a"

!urrent throu)h a fine wire that i( in !onta!t with the (am&"e. *hen the wire )et( (uffi!ient"' hot,

the (am&"e i)nite(.

i)ure 1: Cutaway view of a bomb calorimeter, in which reactions occur atconstant volume.

#o !a"!u"ate the heat of !ombu(tion from the mea(ured tem&erature in!rea(e in the

!a"orimeter, it i( ne!e((ar' to 5now the heat !a&a!it' of the !a"orimeter, C !a"orimeter . #hi( i(

norma""' a(!ertained b' !ombu(tin) a (am&"e that )i$e( off a 5nown uantit' of heat. or

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e%am&"e, it i( 5nown that !ombu(tion of e%a!t"' 1 ) of ben7oi! a!id, 6 2, in a bomb

!a"orimeter &rodu!e( 26.3; 5< of heat. Su&&o(e that 1 ) of ben7oi! a!id i( !ombu(ted in our

!a"orimeter and it !au(e( a tem&erature in!rea(e of =.>22 . #he heat !a&a!it' of the !a"orimeter

i( then )i$en b' 26.3; 5

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;. After the ra&id ri(e &eriod, the tem&erature( at 1 min. inter$a"( wa( re!orded unti"

the differen!e between (u!!e((i$e readin)( ha( been !on(tant for = min.9. or the "i uid fue" (am&"e, !a"!u"ate the heat of !ombu(tion u(in) the formu"a

be"ow:

W = H . g+ e1 + e 3

t Eq .2

. *ata and +esultshar)ed:

Benzoic Acid

Time (1 min. forinterval)

Temperature˚ C

1 28.882 28.883 28.! 28." 28. 1# 28. 1$ 3%.28 31.2

31.31% 31.3

W = H . gt

W =26.454 KJ

kg31.3 − 28.88

= 10.92 KJ ˚ C

Coal:

Time (1 min. forinterval)

Temperature˚ C

1 32.12 33.23 33."

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! 33.#" 33.8# 33.8"$ 33.8$8 33.

33. 21% 33. 2

W = H . g− e 1 − e 3

g

W =10.92 KJ

kg (33.92 − 32.1 )− 15 − 6.35

1 g = 17.32 KJ

g

!. Conclusion#he eat of !ombu(tion of ben7oi! a!id wa( determined to identif' the

heat of !ombu(tion of !oa" whi!h wi"" be the ne%t (te&. rom the !a"!u"ation(, the

heat of !ombu(tion of the ben7oi! a!id wa( 10.92 KJ ˚ C a"(o the heat of

!ombu(tion of the !oa" wa( 17.32 KJ

g . #hi( $a"ue he"&( u( to under(tand the

ener)' that !ou"d be u(ed for an' (am&"e for a wide $ariet' of a&&"i!ation(.

!!. iblio rap#y #ttp,-- ps.pren#all.com- ps-media-ob/ects-0 -0134 15-blb 3 3.#tml

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