Polar covalent bond- a bond where atoms are unevenly shared due to a larger difference in electronegativity of the bonded elements.
Non-polar covalent bond- These are bonds between elements with a low difference in electronegativity. Electrons are shared equally in these bonds between the elements.
Ionic bonds- have such large difference in electronegativity that they take/give electrons to the element they are bonded to. They do not share electrons at all. Bonds between a non-metal and a metal.
You should read up on Proust's law, better known as the Law of Definite Proportions. This is a chemical law that defines your question more generally, on why the ratio of elements and ions are always fixed.
Basically, this compound Magnesium(II) Chloride is MgCl2 because it has the same number of protons, neutrons, and electrons all the way. This defines the properties of the compound or atom.
Answer:
May I assume "ethanol acid is just ethanol (it has one slightly acidic H atom). If so, the molar mass is 46.02 g/mole.
Explanation:
We have 30 cm^3 [30 ml] of 1.0 M (1 mole/liter) [1 dm³ = 1 liter].
That is 1 mole/liter. 30 ml would contain (0.030 liter)*(1 mole/1 liter) = 0.03 moles.