Answer:
An exothermic process releases heat, causing the temperature of the immediate surroundings to rise. An endothermic process absorbs heat and cools the surroundings.
<h2>Answer : Option B) Hydrogen</h2><h3>Explanation :</h3>
All fossil fuels contains hydrocarbons in it. Amongst the given options hydrogen is the correct answer. Except that it contains carbon in it. Hydrocarbons are those class of compounds which contains hydrogen and carbon as element in it.
They are considered to be good fuels because they naturally bring out complete combustion as they contain hydrogen and carbon in its compound form.
Answer: Thus the correct option is D. All of the above describe a mole
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass in grams.
1 mole of every substance contains avogadro's number 
of particles.
Mole is the S.I unit for measuring the amount of substance. It is often used to measure large number of particles.
Thus the correct option is D. All of the above describe a mole
