Usually (ignoring transition metals, as they kinda get trickier), the element's valency can be found out by its group (column) number. Usually, we ignore the transition metal block while counting these columns, so Aluminium is in group 3, for example. Since Aluminium is in group 3, it has 3 valence electrons.
Answer:
closer to F because fluorine has a higher electronegativity than carbon
Explanation:
Electronegativity refers to the ability of an atom in a bonding situation to draw the shared electrons of the bond closer to itself.
Electronegativity increases across the period and decreases down the group. A highly electronegative atom draws the shared electron pair of a bond towards itself.
When two atoms are bonded together, the electron pair is always drawn closer to the atom that has a higher electronegativity.
Hence, the electron pair in a C-F bond could be considered closer to F because fluorine has a higher electronegativity than carbon.
Answer: The partial pressure of the dry oxygen is 742 torr
Explanation:
Dalton's Law of Partial Pressure states that the total pressure exerted by a mixture of gases is the sum of partial pressure of each individual gas present. Thus 
Given; Total pressure = 762 torr
partial pressure of water = 19.8 torr
partial pressure of dry oxygen = ? torr
Total pressure = partial pressure of water + partial pressure of dry oxygen
762 torr = 19.8 torr = partial pressure of dry oxygen
partial pressure of dry oxygen = 742 torr
The partial pressure of the dry oxygen is 742 torr
175.8 g NaCl to moles:
(175.8 g)/(58.44 g/mol) = 3.008 mol NaCl
Molarity = moles of solute/volume of solution in liters
(3.008 mol NaCl)/(1.5 L) = 2.0 M.
The molarity of this solution would be 2.0 M.
