17 TEMPERATURE AND HEAT 17 1 17 2 17 3 17 4 T K 9 5 62 8 32 T 32 81 0 F T 9 T F C5 9 5 56 7 32 134 1 F 9 5 31 1 32 88 0 F IDENTIFY and SET UP EXECUTE a F T b F T c F EVALUATE Fahrenheit degrees are smaller than Celsius degrees so it takes more F than C to express the difference of a temperature from the ice point IDENTIFY and SET UP To convert a temperature between C and K use C T from F to C subtract 32 and multiply by 5 9 To convert from C to F multiply by 9 5 and add 32 To convert a temperature difference use that Celsius and Kelvin degrees are the same size and that 9 F 5 C EXECUTE a C T 98 4 F b K T c 7 C 7 K 7 C T 9 d T 4 0 C C5 F 160 C T 9 T C5 F 5 e T 32 F 9 EVALUATE Celsius Fahrenheit conversions do not involve simple proportions due to the additive constant of 32 but Celsius Kelvin conversions require only simple addition subtraction of 273 15 IDENTIFY Convert T SET UP T T 9 T F C5 7 C 9 F 5 C 13 F 32 273 15 40 273 15 313 K is the same on the Celsius and Kelvin scales 180 F T 9 T C5 F 9 40 32 5 273 15 39 2 F 256 F T T K C 9 4 0 5 160 T C T C 273 15 between different scales T K 160 273 15 113 K T K T K 273 15 9 5 104 F 273 15 36 9 277 K 273 15 32 5 9 To convert 9 5 105 310 4 0 36 9 C 100 C 273 15 273 15 273 15 314 K so 41 C T C F 32 1 C T C 32 32 32 41 32 32 9 5 EXECUTE a T 49 0 F T 49 0 F 27 2 C b T 100 F T 100 0 F 1 C 9 F 5 1 C 9 F 5 55 6 C T F T F 32 C EVALUATE The magnitude of the temperature change is larger in F than in C T IDENTIFY Set C T T and F K T 9 SET UP T T and C K C5 gives T 9 EXECUTE a F T T T T C 5 gives 5 T T T T b F 9 T T EVALUATE Since K 273 15 C agree T 32 273 15 F T 40 C T 40 F 40 5 9 32 273 15 32 273 15 5 9 and 273 15 T K 32 9 4 and 575 F 575 K there is no temperature at which Celsius and Kelvin thermometers 575 Copyright 2012 Pearson Education Inc All rights reserved This material is protected under all copyright laws as they currently exist No portion of this material may be reproduced in any form or by any means without permission in writing from the publisher 17 1 17 2 Chapter 17 17 5 17 6 17 7 1 K 1 C IDENTIFY Convert T 9 SET UP 5 9 T F 5 T 10 0 C K T C in kelvins to C and to F F T C 9 5 10 0 C 18 0 F value EXECUTE a b EVALUATE Kelvin and Celsius degrees are the same size Fahrenheit degrees are smaller so it takes more of them to express a given T IDENTIFY Convert KT to CT and then convert CT to FT T T SET UP K C T EXECUTE a C b C 95 273 15 7 c EVALUATE All temperatures on the Kelvin scale are positive CT is negative if the temperature is below the freezing point of water T IDENTIFY When the volume is constant 2 T 1 T 9 T and 273 15 C5 F 400 273 15 127 C T 178 C F 9 5 178 15 32 7 9 5 1 55 10 32 2 79 10 F T T C 1 55 10 9 5 126 85 32 260 F 32 T F T F 273 15 1 55 10 C 289 F for T in kelvins p 2 p 1 7 7 Figure 17 7 in the textbook gives that the temperature at which 273 16 K T T triple SET UP 2CO solidifies is CO2 T 2 T 1 EXECUTE p 2 p 1 195 K 1 35 atm 195 K 273 16 K 0 964 atm 17 8 EVALUATE The pressure decreases when T decreases IDENTIFY Apply Eq 17 5 and solve for p SET UP 325 mm of mercury p triple EXECUTE p 325 0 mm of mercury 444 mm of mercury 373 15 K 273 16 K 17 9 EVALUATE mm of mercury is a unit of pressure Since Eq 17 5 involves a ratio of pressures it is not necessary to convert the pressure to units of Pa IDENTIFY and SET UP Fit the data to a straight line for EXECUTE a If the pressure varies linearly with temperature then p T and use this equation to find T when p 0 p 1 T 2 T 1 p 2 170 0 Pa C and p to solve for T 0 p 2 T 2 Apply p 0 1 p 1 T 1 p p 1 T T 1 p 1 T T T b Let 1 100 C T is in kelvins 1 p 2 p 1 T 2 T 1 4 4 6 50 10 Pa 4 80 10 Pa with 1 100 C 0 01 C T T T 1 0 01 C 0 01 C 4 4 80 10 Pa 170 Pa C T 0 01 C and 2 282 C 6 50 10 Pa 4 0 01 273 15 100 273 15 use Eq 17 4 to calculate 2p Eq 17 4 says 2 1 T T p p 2 1 where 4 76 10 Pa this differs from the 4 4 80 10 Pa 4 that was 17 10 measured so Eq 17 4 is not precisely obeyed EVALUATE The answer to part a is in reasonable agreement with the accepted value of 273 C IDENTIFY 1 K 1 C SET UP On the Kelvin scale the triple point is 273 16 K EXECUTE 9 5 273 16 K 491 69 R so F and R 1 K 1 C 9 5 9 5 T triple Copyright 2012 Pearson Education Inc All rights reserved This material is protected under all copyright laws as they currently exist No portion of this material may be reproduced in any form or by any means without permission in writing from the publisher Temperature and Heat 17 3 17 11 17 12 17 13 17 14 17 15 17 16 17 17 1 2 10 C EVALUATE One could also look at Figure 17 7 …