Answer:
B) it is endothermic and the temperature decreased
Explanation:
Chemical reactions can be classified as endothermic and exothermic.
Endothermic reactions proceed with the absorption of heat energy (q) and have a positive value for q.
In contrast, Exothermic reactions proceed with the liberation of heat energy (q) and have a negative value for q.
It is given that the value of q = +450 J. Since q is positive, this implies that heat energy is absorbed from the surroundings resulting in a fall in temperature. Hence the reaction is endothermic.
Answer:
Hydrogen is a very reactive element. It doesn't exist as a single atom in nature. Neither do any of the other binary nonmetals -- nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. They're too prone to react with something. They react with each other and form binary molecules because the binary molecules are more stable than single atoms (by a lot!). Compounds with other atoms are even more stable, so hydrogen reacts with oxygen to form water, and chlorine reacts with sodium to form table salt.
Explanation:
Answer:-
KOH determines how much Mg(OH)2 is made.
2 mol of Mg(OH)2 formed
Explanation:-
The balanced equation is
MgCl2 + 2KOH --> Mg(OH)2+ 2KCI,
From seeing the coefficients we notice
2 mol of KOH reacts with 1 mol of MgCl2
4 mol of KOH reacts with 1 x 4 / 2 = 2 mol of MgCl2
3 moles of MgCl2 was added but only 2 mol react.
So we see there is excess MgCl2 .
Hence KOH is the limiting reactant.
So KOH determines how much Mg(OH)2 is made.
We see from the balanced chemical equation,
2 mol of KOH gives 1 mol of Mg(OH)2.
4 mol of KOH will give 1 x 4 /2 = 2 mol of Mg(OH)2.
Answer:
Due to oxidation process apple gets brown color.
Explanation:
When we cut the apple it turn brown in color because of the oxidation process. The peel of apple protect it from the oxidation. When the apple is peel off the oxygen and water molecules in air react with it and oxidation take place. The oxidation process is very efficient in ambient temperature.
For example, if the peal off apple is placed into the refrigerator it take a time to got oxidize and turn brown, but if it is placed in room temperature it quickly turn brown.
when oxygen is react with peel off apple , it trigger the polyphenol oxidase enzyme to oxidize the phenolic compound and quinones are formed which then react with amino acids and produced brown color.
Answer:
BaCl₂ and H₂SO₄
Explanation:
The reaction is the precipitation of BaSO₄ from solution.
This means that our reactants must contain the Ba ion and SO₄²⁻ ion. The reactants that meet this criteria are the; BaCl₂ aand H₂SO₄
The reaction is given as;
BaCl₂ + H₂SO₄ --> BaSO₄ + 2HCl
