Flashcards in Laws Of Thermodynamics. Deck (11):

1

## What is molar heat capacity ?

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Molar heat capacity is the heat required to raise the temperature of 1 mole of any substance by 1 C or 1 K.

It's denoted by C.

2

## What is the formula of molar heat capacity ?

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Q= nC(T'-T).

Molar heat capacity of liquids and solids is almost constant whereas it varies in gases.

3

## What is denoted by Cv and Cp?

### Cp is molar heat capacity due to isobaric process and Cv is molar heat capacity due to isochoric process.

4

## What is the first law of thermodynamics ?

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Q= ΔU + W.

It's the law of conservation of energy.

5

## How to find work done using the first law of thermodynamics ?

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W= p(Vf-Vi)=pΔV.

Is p is constant it means the process is adiabatic.

Work done can also be obtained by tea under p-V diagram with projection on V axis.

6

## In the first law of thermodynamics , what can you say about the sign of work done in various scenarios in p vs V graph?

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W=+ve as volume increases.

W=-ve as volume decreased.

W=0 if volume is constant.

W=+ve as cyclic process is clockwise with p on y axis

W=-ve as cyclic process is anti-clockwise with p on y axis.

7

## Using the first law of thermodynamics, what is the formula of change is internal energy ΔU?

### ΔU= n Cv ΔT. If either three terms are unknown then we can calculate ΔU by ΔU=Q-W.

8

## Using the first law of thermodynamics , what is the formula for heat exchange Q?

### Q= n C ΔT. If all the three quantities are unknown then, calculate Q=ΔU+W.

9

## What can you say about isobaric process in term of x and slope ?

### In isobaric process, x=0, therefore slope= 0.

10

## What can you say about isothermal process in terms of x and slope ?

### In isothermal process , x=1 and therefore slope = p/v.

11