Question

A) Half kg of a given fuel produces 10,000 kl of energy on burning. What is the calorific value of the fuel ?​

Answer 1

Answer:

(a) What is a fuel ? Give five examples of fuels.

(b) What are the characteristics of an ideal fuel (or good fuel)?

(c) The calorific value and ignition temperature of fuel A are 55 kj/g and 80  

o

C. respectively.

These values for fuel B are 80 kj/g and 10  

o

C, respectively. On burning, the fuel A produces CO  

2

​  

and H  

2

​  

O while the fuel B produces CO  

2

​  

,CO and SO  

2

​  

. Give three points of relative advantages and disadvantages of these two fuels.  

Answer

(a) The material which is burnt to produce heal energy is known as a fuel.  

Ex. Wood, coal, LPG, kerosene, diesel etc.

(b) Characteristies Of ideal fuel  

(i) It should have high calorific value.  

(ii) It should burn without giving out any smoke or harmful gases.  

(iii) It should have proper ignition temperature.  

(iv) It should cheap and easily available.  

(c) Fuel A: Lower calorific value of 55 kJ/g (Disadvantage) a Moderate ignition temperature of 80  

o

C (Advantage)  

iii. No harmful gases produced (Advantage)  

Fuel B:  

i. High calorific value of 80 kJ/g (Advantage)  

ii. Very low ignition temperature of 10  

o

C (Disadvantage)  

iii. Harmgul gases like CO and SO  

2

​  

 produced (Disadvantage)

Explanation:

Answer 2

Given,

Half kg of a given fuel produces 10,000 kg of energy on burning.

To Find,

The Calorific value of the fuel.

Solution,

We can solve this mathematical problem using mathematical formulas.

Firstly, convert heat energy in Joule.

10,000 kl = 10,000 × 10³ Joule

Calorific value = $\frac{Heat released (in Joule)}{Mass of fuel (in gram)}$

⇒$\frac{10000 * 10^{3} J }{4.5 * 10^{3} gm }$

⇒ 40000 Joule/gram    

⇒ 40 KJ/gm                                                         [ 1 KJ = 1000 Joule]

Hence, the Calorific value of the fuel is 40 KJ/gm.