Why are cirrocumulus clouds sometimes called mackerel clouds

Often on a topographic map, every fifth contour line is darkened. what is this line called? a. key b. slope c. benchmark d. index contour

Write the empirical chemical formula of calcium with a mass percent of 38.8, phosphorus with a mass percent of 20.0, and oxygen with a mass percent of 41.3.

If 90.0 grams of ethane reacted with excess chlorine, how many grams of dicarbon hexachloride would form