Answer:
B
Explanation:
Asteroid - A rock that rvolves arounf the sun / star.
Moon - A natural satillite that revolves around earth/ planet.
I believe it is either A or B
Answer : The volume of 4.9 M
stock solution used to prepare the solution is, 12.24 ml
Solution : Given,
Molarity of aqueous
solution = 1.20 M = 1.20 mole/L
Volume of aqueous
solution = 50.0 ml = 0.05 L
(1 L = 1000 ml)
Molarity of
stock solution = 4.9 M = 4.9 mole/L
Formula used :

where,
= Molarity of aqueous
solution
= Molarity of
stock solution
= Volume of aqueous
solution
= Volume of
stock solution
Now put all the given values in this formula, we get the volume of
stock solution.

By rearranging the term, we get

Therefore, the volume of 4.9 M
stock solution used to prepare the solution is, 12.24 ml
Answer:
5 000 000 (5 million atoms)
Explanation:
Let us assume that a vanadium atom has a spherical shape.
diameter of a sphere = 2 x radius of the sphere
Thus,
Radius of a vanadium atom = 130 pm
= 130 x
m
The diameter of a vanadium atom = 2 x radius
= 2 x 130 x
= 260 x
m
Given a distance of 1.30 mm = 1.30 x
m,
The number of vanadium atoms required to span the distance = 
= 5000000
Therefore, the number of vanadium atom that would span a distance of 1.30 mm is 5 million.