Question

An insulated rigid vessel contains a mixture of fuel and air. The mixture is ignited by a minute spark. The contents of vessel experience

Answer 1

Options missing in question :-

1)Increase of temperature,pressure and energy  

2)Decrease of temperature,pressure,and energy  

3)Increase of temperature,pressure but no change in energy  

4)Increase of temperature and pressure but decrease in energy.

Actual answer is  

Increase of temperature,pressure but no change in energy  

When you ignite a flammable substance, combustion process occurs this results in increased temperature and pressure.  Energy remains constant in this process.

Answer 2

Answer:

The content of vessel increase in temperature and pressure but no change in energy.

Explanation:

The total amount of energy stays constant in accordance with the First Laws of Thermodynamics.

First law of Thermodynamics:

• According to the First Law of Thermodynamics, heat is a type of energy, and  thermodynamic processes are controlled by the principle of energy conservation.
• Heat energy cannot be created or destroyed, hence this means. But it can be moved from one place to another and changed into and out of various types of energy.

First Law of Thermodynamics expressions can be expressed as

δQ = dU + δW

Due to the insulation of the vessel and the rigidity of the border, no heat is lost through the system.

A little spark that ignites the mixture causes a fast increase in temperature.

Also from from the perfect gas equation

PV = mRT

where

P = absolute pressure

V= volume

m = mass

R = gas constant

T = absolute temperature

Here Volume remains constant, m and R also constant for a gas.

So P ∝ T

When there is a increase in temperature, then pressure also get increases

Final answer:

An insulated rigid vessel contains a mixture of fuel and air. The mixture is ignited by a minute spark. The contents of vessel experience increase in temperature and pressure but no change in energy.

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