How many ml of a 0.10 M NaOH solution are needed to neutralize 15 ml of a 0.20 M H3PO4 solution

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

List four observations that indicate that a chemical reaction may be taking place

Match the mixture with the substance// i really need on this guys (it’s a pic btw)