Idk really but i hope you figure out the answer im not on that yet.
1 mole ----------- 22.4 L ( at STP )
3.5 mols --------- ?
V = 3.5 x 22.4 / 1
V = 78.4 L
hope this helps!
Answer: The reaction is exothermic
The
value is negative.
Heat is a product.
Explanation:

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and
for the reaction comes out to be positive.
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and
for the reaction comes out to be negative.
The substances which are written on the left side of the arrow are reactants and the substances which are written on the right side of the arrow are products. Thus heat is a product.
Answer: concentration
Explanation:
Concentration refers to the amount of a substance present in a sample. The more molecules of a substance present in a sample, the greater its concentration. The less molecules of a substance in a sample, the lesser the concentration. We are often concerned about analytically determining the concentration of a substance using diverse analytical methods in chemistry.