Answer : The molarity of solution is, 1.00 M
Explanation : Given,
Moles of
= 0.500 mol
Volume of solution = 0.500 L
Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.
Formula used :

Now put all the given values in this formula, we get:

Therefore, the molarity of solution is, 1.00 M
Answer. Chemical reaction had occurred and both the powders are different substances.
Explanation:
As density is an intensive property of the substance.Which means that different substance have different densities.
Density = 
Density of powder 1, 
Density of powder 2, 
On comparing both the densities of the powders we can say that both the substances are different. So we can conclude that the chemical reaction had occurred.
Answer:
Each molecule contains one atom of A and one atom of B. The reaction does not use all of the atoms to form compounds.
A + B ⟶ Product
Particles: 6 8 6
If six A atoms form six product molecules, each molecule can contain only one A atom.
The formula of the product is ABₙ.
If n = 1, we need six atoms of B.
If n = 2, we need 12 atoms of B. However, we have only eight atoms of B, so the formula of the product must be AB.
Thus, 6A + 6B ⟶ 6AB, with two B atoms left over.
Explanation:
Credit goes to @znk
Hope it helps you :))
D has a total of four significant figures.