Answer: Anna stated that ionic compounds have high melting point and low boiling point. The error in the statement is that ionic compound have low boiling point, instead ionic compounds have high boiling point, because in an ionic compound, the force of attraction working between two ions is very strong and hence the bonds present are very strong, and a lot of energy is needed to break them
The Jetliner will travel a total of 1518 meters if flying for 6 hours.
<u>Answer:</u> The percent composition by mass of hydrogen in given compound is 6.33 %
<u>Explanation:</u>
We are given:
A chemical compound having chemical formula of 
It is made up by the combination of 1 nitrogen atom, 5 hydrogen atoms, 1 carbon atom and 3 oxygen atoms
To calculate the percentage composition by mass of hydrogen in the compound, we use the equation:

Mass of compound = ![[(1\times 14)+(5\times 1)+(1\times 12)+(3\times 16)]=79g/mol](https://tex.z-dn.net/?f=%5B%281%5Ctimes%2014%29%2B%285%5Ctimes%201%29%2B%281%5Ctimes%2012%29%2B%283%5Ctimes%2016%29%5D%3D79g%2Fmol)
Mass of hydrogen = 
Putting values in above equation, we get:

Hence, the percent composition by mass of hydrogen in given compound is 6.33 %
If an atom has 2 protons, then it must also have 2 electrons for there to be no charge. An extra electron will cause for you to have a negative charge, and if you have more protons than electrons, then you will have a positive charge. :)
Sc (neutral) [Ar] 3d1 4s2
Sc+ [Ar] 3d1 4s1
Sc2+ [Ar] 3d1
hope this helped!