Styles 1. Please convert temperature 25°C to Fahrenheit scale and Kelvin scale.

Question

Styles 1. Please convert temperature 25°C to Fahrenheit scale and Kelvin scale. 2. a) How much heat is needed to warm up a 1000-g steel block from 20°C to 100 °C? (c-0.11cal/g"c) b) How much heat is needed to warm up a 1000-g water from 20°C to 100°C? (c 1.0 cal/g°C) 3. a) In a thermodynamic system, gas expends from 1 m3 to 3 m3 while keeping a constant pressure 5000 Pa. How much work is done by the gas? b) During this process, if the heat flows into the system is 3000 cal, what's the internal energy change of the system?

Explanation / Answer

1.

We know that

K = 273 + C

when Temperature is 25 C

then in Kelvin

K = 273 + 25 = 298 K

Also,

F = 9C/5 + 32

Since C = 25

F = 9*25/5 + 32 = 77 F

2A.

Heat required is given by

Q = m*C*dT

Using given values:

Q = 1000*0.11*(100 - 20) = 8800 cal = 8.8 k-cal

2B

In this case

Q = 1000*1*(100 - 20) = 80000 cal = 80 k-cal

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