1) Answer: A hot pack feels warm when chemicals in it combine.
Explanation: Reactions or process in which heat is released(produced) are known as exothermic reactions or process and those in which the heat is absorbed are known as endothermic reactions or process.
If a beaker feels cools when chemical in it react then it means the chemicals have absorbed the heat energy from its surroundings and so it is an example of an endothermic process.
A hot pack feels warm when chemicals in it combine means the energy is released in the chemical reaction and so it is an example of an exothermic process.
Plants use the sun's energy for photosynthesis which is a process of forming food for the plants. Energy acts as a reactant in this process and so it is an example of endothermic process.
Frying an egg by heating it on a stove is an example of an endothermic process as the heat is required to fry the egg.
So, the only exothermic process is the second one, "A hot pack feels warm when chemicals in it combine."
2) In the given equation, heat is written as a product means the heat is released in the equation and so it is an example of an exothermic reaction.
So, the correct choice is the last one " It is exothermic because energy is released."
Answer :
(a) The density of mercury is, 13.6 g/ml
(b) The mass of 120.0 ml of mercury is, 1632 grams
Explanation :
(a) Now we have to calculate the density of mercury.
<u>Given :</u>
Volume of mercury = 25.0 ml
Mass of mercury = 340.0 g
Formula used :
Therefore, the density of mercury is, 13.6 g/ml
(b) Now we have to calculate the mass of 120.0 ml of mercury.
As, 25.0 ml of mercury has mass = 340.0 g
So, 120.0 ml of mercury has mass = 
Therefore, the mass of 120.0 ml of mercury is, 1632 grams
Answer:
43.7
Explanation:
mole is equal mass concentration/ moler mass of MgCl²
Mass is measured in kilograms.
It changes state
Meaning, it goes from solid to liquid, making it change its state. Hope this helped.
