When two fluorine atoms react to produce a fluorine molecule, Energy is released as a bond is formed. The answer is number 4. IT takes energy to form a bond from two atoms that is why energy is releases after the bond is formed.
B. Drying wood in a shed
C. Melting ice to obtain water
D. Evaporating alcohol into vapor
Coal combustion causes a chemical change. Burning coal in a furnace will result in a chemical change. Therefore, option A is correct.
A chemical change is the transformation of one material into another, the formation of new materials with different properties, and the formation of one or more new substances. It occurs when one substance reacts with another to form a new substance.
Coal combustion causes a chemical change. The main component, carbon, is converted to carbon dioxide when coal is burned. This process is irreversible.
When carbon is burned, it produces carbon dioxide, and hydrogen produces water. Each of these reactions generates a different amount of heat. Because this process cannot be reversed, coal combustion is a chemical change.
Thus, option A is correct.
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Answer: Value of impulse is
Explanation: lmpulse is defined as the amount of force acting over a short time interval 't' which is equal to the change in momentum of the body having mass 'm'.
Mathematically,
And,
Given:
Putting values in above equation, we get: