i can't give you a full answer to the lack of info, but everything goes somewhere. take the making of water, for instance. 2 Hydrogen and 1 Oxygen <u>must</u> equal H2O (2 parts hydrogen and 1 part oxygen) after being made.
Long story short: what goes in must have the same amount of atoms after the chemical reaction.
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."
The answer is either A or B I’m not sure
M = n/V
.5M = n/.100 L
n = .1 L * .5M
n= .05 mols of MgCl2
mass of MgCl2 = .05 mols of MgCl2 * 95.211 grams/ 1 mol of MgCl2
mass of MgCl2 = 4.76 grams
4.76 grams of MgCl2 is needed to make 100 ml of a solution that is .500M, in chloride ion. Bolded = confused
