The only one that I can do without google is 47. Sorry that I can't answer the others. The answer to 47 is this: you know that the western side of the hill has the steepest slope because the ovals showing altitude are way closer together. The closer the circles/ovals are, the steeper the slope is.
Sorry if this doesn't help much, but I answered what I could without cheating.
Foxeslair
The statement that best explains why magnesium and chlorine combine in a 1:2 ratio is; Magnesium has two valence electrons, and chlorine can accept one electron in its outer shell.
The number of electrons that an atom of an element has in its outermost shell determines the chemical formula of the compounds formed by atoms such elements.
Magnesium is in group 2, as such it has two electrons in its outermost shell while chlorine in group 17 only accepts one electron in its outermost shell. This one electron will give chlorine an inert gas configuration while the loss of two electrons give magnesium an inert gas configuration.
Therefore; The compound MgCl2 is formed in the ratio of 1:2 because Magnesium has two valence electrons, and chlorine can accept one electron in its outer shell.
Learn more: brainly.com/question/11527546