You can determine an element based on its protons due to the atomic number.
Atomic number is the number of protons in an atom and you can locate it on your periodic table as the number above the letter. Each element has a different number of protons and because of that you can find the element on the periodic table based on its atomic number.
Answer : The volume for 6.0m HCl solution required = 62.5 ml
Solution : Given,
Initial concentration of HCl solution = 6.0m
Final concentration of HCl solution = 1.5m
Final volume of HCl solution = 250 ml
Initial volume of HCl solution = ?
Formula used for dilution is,

where,
= initial concentration
= final concentration
= initial volume
= final volume
Now put all the given values in above formula, we get the initial volume of HCl solution.

= 62.5 ml
Therefore, the volume for 6.0m HCl solution required = 62.5 ml
A condensed structural formula is a simple way of representing organic compounds.
The given organic compounds and condensed structural formula is presented below;
- The condense structural formula of alkene 2,7 Undecadiene with molecular formula C₁₁H₂₀ is in the image uploaded.
- The condense structural formula of 2,8 Nonene with the molecular formula C₉H₁₈ is in the image uploaded.
- The condense structural formula of 5 Decyne with the molecular formula C₁₀H₁₈ is in the image uploaded.
Learn more about structural formula here: brainly.com/question/514499
Again, I believe the answer would be D. seawater.
If the sign is positive then the reaction is feasible and could take place. If it is negative it is not likely the reaction will take place as it is not feasible