Answer: A) grinding coffee beans
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.
1. Grinding coffee : Only change in size takes place, thus a physical change
2. Baking a cake: the chemical reaction occurs by combination of flour with oxygen , thus a chemical change.
3.:converting water to hydrogen and oxygen: The decomposition iof water takes place, thus is a chemical change
4.Burning of coal: the chemical reaction occurs by combination of carbon with oxygen , thus a chemical change.
We have the value of
Total energy produced in the chemical reaction=653 550 KJ
Time needed=142.3min
To calculate the rate of energy transfer, that is the amount of energy produced per minute.
Rate of energy transfer=
=
=4592.76 KJ min⁻¹
So, the rate of energy transfer is 4592.76 KJ min⁻¹.
Fishes yes according to the age, reptiles yes
The answer is Hydrogyn bonding. It keeps the water molocules bonded together and in a liquid state, without it it'd be in a gashious state.
