Do certain types of chemical reactions tend to be endothermic? why?

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

What is the percent composition of ca(oh)2? 37.7% ca, 53.0% o, and 10.3% h 45.5% ca, 38.2% o, and 16.3% h 54.0% ca, 43.0% o, and 2.7% h 64.7% ca, 27.0% o, and 8.3% h

In in , is to a 28.4-g (1-oz)−23.0 °c to −1.0 °c?