Answer:
C.
Explanation:
Answer A is incorrect because a compound doesn't have to be made with only metals.
Answer B is incorrect because that is actually the definition of a pure element.
Answer C is correct because to make a compound, there has to be a chemical reaction where bonds are formed and an entirely new substance is created.
Answer D is incorrect because compounds cannot be separated by physical means.
Hope this helps :D
The mass of 4.5 moles of sodium fluoride is 189g
Exothermic type of reaction is taking place because this type of reaction generates heat energy.
<h3>What is exothermic reaction?</h3>
Exothermic reactions refer to those chemical reactions that produce heat energy and release that heat energy to the surrounding environment.
So we can conclude that exothermic type of reaction is taking place because this type of reaction generates heat energy.
Learn more about reaction here: brainly.com/question/26018275
Answer: 
Explanation:
According to ideal gas equation:
P = pressure of gas = 0.987 atm
V = Volume of gas = 12 L
n = number of moles = 0.50
R = gas constant =
T =temperature = ?
Thus the temperature of a 0.50 mol sample of a gas at 0.987 atm and a volume of 12 L is
