You must use 2.50 mL of the concentrated solution to make 10.0 mL of the dilute solution.
We can use the dilution formula
<em>V</em>_1<em>C</em>_1 = <em>V</em>_2<em>C</em>_2
where
<em>V</em> represents the volumes and
<em>C</em> represents the concentrations
We can rearrange the formula to get
<em>V</em>_2 = <em>V</em>_1 × (<em>C</em>_1/<em>C</em>_2)
<em>V</em>_1 = 10.0 mL; <em>C</em>_1 = 5.00 g/100. mL
<em>V</em>_2 = ?; ____<em>C</em>_2 = 20.0 g/100. mL
∴ <em>V</em>_2 = 10.0 mL × [(5.00 g/100. mL)/(20.0 g/100. mL)] = 10.0 mL × 0.250
= 2.50 mL
Yes it is just in the back which still makes it negative
Answer:

Explanation:
Although the context is not clear, let's look at the oxidation and reduction processes that will take place in a Fe/Sn system.
The problem states that anode is a bar of thin. Anode is where the process of oxidation takes place. According to the abbreviation 'OILRIG', oxidation is loss, reduction is gain. Since oxidation occurs at anode, this is where loss of electrons takes place. That said, tin loses electrons to become tin cation:

Similarly, iron is cathode. Cathode is where reduction takes place. Reduction is gain of electrons, this means iron cations gain electrons and produce iron metal:

The net equation is then:

However, this is not the case, as this is not a spontaneous reaction, as iron metal is more reactive than tin metal, and this is how the coating takes place. This implies that actually anode is iron and cathode is tin:
Actual anode half-equation:

Actual cathode half-equation:

Actual net reaction:

1.008x10^16 Joules. Technically a theory and not a law. but E=MC^2!
energy=mass ×speed of light squared.
J=kg×(m/s)^2