Answer:- 
Explanations:- Transition elements shows variable oxidation states. So, while naming these compounds we use the roman numerals to tell their oxidation states.
For example, if someone writes just Iron oxide then it would not be correct since Iron could be in +2 or +3 states. So, it might be or 
. So, the right was is to mention the oxidation state of the transition metal.
If the name is written as Iron(II) in a compound then it means there is +2 charge on iron and it is .
Answer:
D
Explanation:
I think they would design a airplane with this new metal first because they have to find the right balance for this new type of metal. They can't just sell a airplane with a new metal that has a different weight immediately they need to test it and design it first.
The dilution formula can be used to find the volume needed
c1v1 = c2v2
Where c1 is concentration and v1 is volume of the concentrated solution
And c2 is concentration and v2 is volume of the diluted solution to be prepared
c1 - 0.33 M
c2 - 0.025 M
v2 - 25 mL
Substituting these values in the equation
0.33 M x v1 = 0.025 M x 25 mL
v1 = 1.89 mL
Therefore 1.89 mL of the 0.33 M solution needs to be diluted up to 25 mL to make a 0.025 M solution
