9
^
^'^-'^'-'-''^
ezing a n d Boiling Point G r a p h
Heat a n d Its M e a s u r e m e n t
H e a t ( o r e n e r g y ) c a nb e m e a s u r e d In units o f calories o r Joules.
W h e n t h e r e Is a t e m p e r a t u r e c h a n g e ( A T ) , h e a t ( Q ) c a n b e
c a l c u l a t e d using this f o r m u l a ;
o
•0
Q ~ m a s s X AT X s p e c i f i c h e a t c a p a c i t y
CO
( A T =• F i n a l T e m p - i n i t i a l
Temp)
a
6
D u r i n g a p h a s e c h a n g e , w e u s e this f o r m u l a ;
Q = m a s s x h e a t of fusion (or h e a t of vaporization)
Solve t h e following
1,
r the following questions using t h echart a b o v e ,
' h a t Is t h e f r e e z i n g p o i n t o f t h e s u b s t a n c e ?
&
' h o t is t h e b o i l i n g p o i n t o f t h e s u b s t a n c e ?
' h a t Is t h e m o l t i n g p o i n t o f t h e s u b s t a n c e ?
j j
5
lis)
15)
h a t letter represents
armed?
t h e r a n g e w h e r e t h e s o l i d is b e i n g
hat letter represents
srmed?
<i'^<
t h e r a n g e w h e r e t h e l i q u i d Is b e i n g
problems,
H o w m a n y Joules o f h e a t a r e g i v e n o f f w h e n 6,0 g o f w a t e r
c o o l f r o m 7 5 " C to'26° C ? ( S p e c i f i c h e a t o f w a t e r =
4.18 j/g^ C) ^. , ^ T^^^-iTs^i,^^
'
2,
H o w m a n y c a l o r i e s a r e g i v e n offBT'fKe w a t e r I n P r o b l e m 1 ?
( S p e c i f i c h e a t o f w a t e r = 1.0 cal/g° C )
3,
H o w m a n y J o u l e s d o e s I t t a k e t o m e l t 3 5 g o f I c e a t 0° C ?
( h e a t o f fusion = 333 j/g)
^.....--.w..—
h a t l e t t e r r e p r e s e n t s t h e r a n g e w h e r e t h e v a p o r Is b e i n g
?rmed? .
hat letter represents
t h e meltlng.of t h e solid?
nq^ letter represents
t h e v a p o r i z a t i o n o f t h e liquid?-^
i g t letter(s) s h o w s a c h a n g e In p o t e n t i a l energy?,, '
^o\) s h o w s a c h a n g e I n l < l n e t l c
4,
H o w m a n y calories a r e g i v e n ot^ w h e n 8 5 g o f s t e a m
c o n d e n s e t o liquid w a t e r ? ( h e a t o f v a p o r i z a t i o n =
539,4 cal/g)
- '
5,
H o w m a n y joules o f h e a t a r e necessary t o raise t h e
t e m p e r a t u r e o f 2 5 g o f w a t e r f r o m 10° C t o 60° C ?
6,
H o w m a n y c a l o r i e s a r e g i v e n ofl^ w h e n 5 0 g o f w a t e r a t 0 "
freezes? ( h e a t o f fusion.= 79,72 cal/g)
^ •—-^-"t
energy?
¥ ^
lot letter represents c o n d e n s a t i o n ?
•....'•^at l e t t e r r e p r e s e n t s c r y s t a l l i z a t i o n ?
P ,
:==SJ_
/ j ^ •
Name:_
Date:
Qass:
Chapter 3 3
Y o u m a y use y o u r notes a n d text to complete the f o l l o w i n g (please s h o w a l l w o r k f o r
p a r t i a l c r e d i t ) : (10 points)
1.) H o w m u c h e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f 4 5 . 7 g o f w a t e r f r o m 2 5 . 0
degrees Celsius, to 37.6 degrees Celsius?
2 . ) I f 2 . 0 8 X lO*^ J o f e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f 0 . 5 6 k g o f a s u b s t a n c e
f r o m 6.5 degrees C e l s i u s t o 4 2 . 4 degrees C e l s i u s , w h a t is the specific heat o f this
3
• c
Name:_
• 1 ' ^
Date:
Class:
Chapter 3 3
Y o u m a y use y o u r notes and text to complete the f o l l o w i n g (please s h o w all w o r k for
p a r t i a l c r e d i t ) : (24 points)
1.) H o w m u c h e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f 2 2 - 7 g o f w a t e r f r o m 3 4 . 0
degrees Celsius, t o37.6 degrees Celsius?
2.) I f 4.08 X - i O M o f energy i sr e q u i r e d to raise t h e temperature o f 0.56 k g o f a substance
f r o m 6.5 degrees C e l s i u s t o2 3 . 4 degrees C e l s i u s , w h a t is the specific heat o f t h i s
substance?
O-.S'oU^^^
- ~ ^ ' >'
3.) H o w m u c h energy isrequired t oraise the temperature o f w a t e r . f r o m- 1 0 . 3 degrees ^ ^
Celsius t o 135-4 degrees Celsius?
f 6&rTeA^
y^fP-j
Ji/^/J^
'J
J
• J"
/
,—
>L
3.^^W3iatjsflie-differencebefayf^fin
e;ylSQsivs-aB4JBteQsiye_g^
'ction 3
^- Describe the three conditions under which heat is transferred. W i e n d e s c r i b i n g t h e c o n d i l i p i f i b y w h i c h a
h o t object c o m e s into contact w i t h a cold object, e x p l a i n h o wt h e s p e e d ^ v ^ & e p a i t i c l ^ j n d
tii^aj^^ilisi
c r e a t e s t h e h e a t t r a n s f e r . E x p l a i n a n d g i v e a n e x a m p l e of a c o n d i t i o n b y wlJ^^SgprglsjioHgon t h e s y s t e m b y
the surromidings, a n d o n e iri w h i c h w o r k is d o n e o n t h e surxotmdings o n t h e system? h i each, h o w d o y o u k n o w
t h a t w o r k h a s b e e n d o n e ? (20 points)
2. Energy C o n v e r s i o n s : C o n v e r t b e t w e e n u n i t s u s e d t o m e a s u r e e n e r g y . N o t e = 1 c a l o r i e i s e q u a l t o 4 . 1 8 4
J o u l e s . (16 points)
a- 3 6 3 7 . 3 J =
3(^Z^3T
^ _
(
cal
b.
2 1 67 cal = ^ 4 ^ ?
.Cal
c.
21.00
_J
d.
-136.5 C a l =
k J = _ _ y _ i ° 0
m
J
lie
T
3. Describe endothermic and exothermic processes and state the function of activation energy. C o m p a r e
the energy levels o f reactants to products i n both the endothermic and exothermic reactions. P r o v i d e a n energy
d i a g r a m t o i l l u s t r a t e y o u r p o i n t W h a t i s t h e r o l e o f a c t i v a t i o n e n e r g y i n a r e a c t i o n ? (18 points)
4, Perform calculations involving specific heat: (38 points)
a . H o w m u c h e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f L Q 2 . 7 8 g o f w a t e r from 1 5 J 2 d e g r e e s C e l s i u s ,
to 8 0 . 8 degrees C e l s i u s ( n o t e ^ t h e specific heat o f w a t e r i s 4 . J 8 4 ^^£2Q2
_
b. I f 4 . 5 8 x 10^ J o f e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f b . 6 3 1 kg"ora"suBktance
i^i. ^ C e l s i u s t o 9 8 . 4 d e g r e e s C e l s i u s , w h a t i s t h e s p e c i f i c h e a t o f t h i s s u b s t a n c e ?
from 9 . 5 d e g r e e s
-r / -"^r I
- r ^ c . H o w m u c h e n e r g y i s r e q u i r e i f t o r a i s e % i e t e r r f p e r a t u r e o f I 5 0 . 6 g w a t e r from - 1 0 0 . 3 d ^ e e s C e l s i u s t o
2 0 5 . 7 d e g r e e s C e l s i u s ( n o t e : s p e c i f i c h e a t o f i c e = 2.O6g70*°C, s p e c i f i c h e a t o f s t e a m = 2 . 0 2 ^ * ' ' C , w a t e r ' s
heat o f fusion = 3 3 3 J/g, water's heat o fvaporization = 129J/g, melting point = 0.00degrees Celsius, boiling
point = 100.0 degrees Celsius)?
5. Explain each section of the following phase change diagram. I n o t h e r w o r d s , w h a t s t a t e ( s o l i d , l i q u i d , or
gas) i s t h e substance a n d w h a t is h a p p e n i n g t o t h e temperature i n each labeled section? W h a t i s t h e m e l ^ n ^
freezing,
b o i l i n g , a n d c o n d e n s a t i o n p o i n t s o f t h e s u b s t a n c e ? ( 2 0 points)
|
njj'
70
0)1., 0
Is
f
0f
4.
P e r f o r m c a l c u l a t i o n s i n v o l v i n g s p e c i f i c h e a t : (31 p o i n t s )
•
•
'
a . H o w m u c h e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f 3 0 2 . 7 g o f w a t e r firom 2 4 . 0 d e g r e e s C e l s i u s ,
to 77.6 degrees Celsius?
O
b.
I f 4 . 2 0 8 X 10'' J o f e n e r g y is r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f 0 . 4 3 1 k g o f a s u b s W c K & d r n
degrees Celsius t o 6 2 . 4 degrees C e l s i u s , w h a t is the specific heat o f this substance?
c. H o w m i i c h e n e f g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f w a t e r f r o m — 2 1 0 . 3 d e g r e e s C e l s i u s t o 2 3 5 . 4
degrees Celsius? i ^ c ^
< f,o£4<^^
- m A t
m
c
y
3
5.
E x p l a i n each section o f the f o l l o w i n g phase c h a n g e diagram. I n other w o r d s , w h a t state (solid, liquid, o r
g a s ) i s t h e s u b s t a n c e a n d w h a t i s h a p p e n i n g t o t h e t e m p e r a t u r e i n e a c h l a b e l e d s e c t i o n ? (20 p o i n t s )
. A
V
2- Energy Conversions: C o n v e r t b e t w e e n u n i t s u s e d t o m e a s u r e e n e r g y . N o t e = I c a l o r i e is e q u a l t o 4 . 1 8 4
[^y^
J o u l e s . (20 points)
a. 4 5 0 0 0 0 J =
^
kJ
b.
45 340000 J =
c.
1257cal =
d.
4 3 0Cal =
^
T
I k^T
X"
^ w
J
" ^^^^^
ODD
^
cal
3. Describe endothermic and exothermic processes and state the function of activation energy. C o m p a r e
the energy levels o f reactants t o products i n both t h e e n d o t h e r m i c a n d e x o t h e r m i c reactions. P r o v i d e a n energy
d i a g r a m t o i l l u s t r a t e y o u r p o i n t W h a t i s t h e r o l e o f a c t i v a t i o n e n e r g y i n a r e a c t i o n ? (18 points)
/
4. Perform calculations involving specific heat: I B pomt^
(Z^.S'/G )
a. H o w m u c h e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e o f 2 2 . 8 ^ f s i l v e r f r o r n 2 5 . 4 d e g r e e s C e l s i u s , t o
6 5 0 . 0 degrees Celsius (note: t h e specific heat o f silver "
b.
I f 6 . 2 5 xs ' l O ' ' J o f e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a t u r e d e g r e e s C e l s i u s t o 6 5 . 5 degrees C e l s i u s , w h a t i s t h e s p e c i f i c h e a t o f this-eefestance?-
c.
H o w m u c h e n e r g y i s r e q u i r e d t o r a i s e t h e t e m p e r a m r e oo ff 2 2 0 . 6 g w a t e r from - 4 5 3
es Celsius t o
2 2 8 . 0 d e g r e e s C e l s i u s ( n o t e : s p e c i f i c h e a t o f i c e = 2 . 0 6 J/g*°C, s p e c i f i c h e a t o f s t e a m = 2 . 0 2 J/g*°C,
w a t e r ' s h e a t o f f u s i o n = 3 3 3 J / g , w a t e r ' s h e a t o f v a p o r i z a t i o n = 2 2 6 0 J / g , m e l t i n g p o i n t = O.OO d e g r e e s ^
C e l s i u s , b o i l i n g p o i n t = 1 0 0 . 0 d e g r e e s C e l s i u s ) ? ^ S p e c ^ f i c f ^ ^ A T of: / I ^ ^ O f ^ ) - 4JQH
^ ' ' ^ ^
rom
22.5
5. Explain each section of the following phase change diagram. I n o t h e r w o r d s , w h a t s t a t e ( s o l i d , l i q u i d , o r
gas) i s t h e substance a n d w h a t i s h a p p e n i n g t o the t e m p e r a t u r e i n each labeled section? W h a t is t h e actual
m e l t i n g , f r e e z i n g , b o i l i n g , a n d c o n d e n s a t i o n p o i n t s o f t h e s u b s t a n c e ? ( 2 0 points)
Use the solubility chart to answer the following: (8 points each)
a.
bc.
W h a t is t h e solubilityo f potassium nitrate at 5 0 degrees Celsius?
H o w m u c h o fit will dissolve i n 342g o f water at 4 0 degrees Celsius?
H o w m u c h water w i l l berequire to dissolve 2 1 2 g o f K C l at 3 0 degrees Celsius?
^2 ^
92-3D0
^
^ 9 05-0
"X
6^ 60D
T
to
j'^z
COD
Ore.
'3
r