Answer:
<em>The correct option is B) two liquids are mixed at room temperature and a gas forms.</em>
Explanation:
A chemical change can be described as a change which results in the formation of a new substance by the reactants. In the option B, two liquids react to form a new product which is a gas. Hence, it is an example of chemical change.
Other options,like option D, is not a chemical change as by crushing a solid no new product is formed. Option C is also not correct because as when salt dissolves in water, no new product is made.
Answer:
Natural chemicals are produced by nature without any human intervention. Synthetic chemicals are made by humans using methods different than those nature uses, and these chemical structures may or may not be found in nature. Stay safe .
Answer: The standard free energy change for a reaction in an electrolytic cell is always positive.
Explanation:
Electrolytic cells use electric currents to drive a non-spontaneous reaction forward.
Relation of standard free energy change and emf of cell
where,
= standard free energy change
n= no of electrons gained or lost
F= faraday's constant
= standard emf
= standard emf = -ve , for non spontaneous reaction
Thus 
Thus standard free energy change for a reaction in an electrolytic cell is always positive.
The answer is GAS. Gas has a physical state characterized by having no definite volume or shape and consisting of neutral particles. or it can also be plasma.
Answer:
2.256 moles of oxygen atoms
Explanation:
CaCo3 is calcium carbonate
every mole of calc carb has 3 moles of O atoms
.752 moles of this has 3 times as many moles of Oxygen atoms
