The structural formula for 2-methylpentane is in Figure 1. It shows all the C-C and C-H bonds explicitly.
The bond-line formula for 2-methylpentane is in Figure 2. We assume that a carbon atom is at the ends and junctions of the lines. We do not show the H atom, but we mentally assume that there are enough to give each carbon a valence of four.
A condensed structural formula is designed to be typed <em>all on one line</em>. We could write the condensed structural formula for 2-methylpentane as either (CH₃)₂CH-CH₂-CH₂-CH₃ or CH₃CH(CH₃)CH₂CH₂CH₃.
The horizontal C-C bonds are <em>optional </em>— you can include or omit them as desired.
Mass percentage of sodium chloride(NaCl) in ocean waters = 3.5 %
That means 3.5 g sodium chloride(NaCl) is present for every 100 g of ocean water.
The given mass of sodium chloride(NaCl) is 45.8 g
Calculating the mass of ocean waters that would contain 45.8 g sodium chloride(NaCl):
= 1309 g ocean water
Therefore, 45.8 g sodium chloride is present in 1309 g ocean water.