Which of the following has kinetic energy? Wind blowing at 3 km/h
A fully stretched elastic band
A boulder sitting on top of a hill
An unused battery

Consider the following reactions. (note: (s) = solid, (l) = liquid, and (g) = gas.) mg(s) + ½o2(g) → mgo(s) + 146 kcal/mole h2(g) + ½o2(g) → h2o(g), δh = -57.82 kcal/mole what type of reaction is represented by the previous two examples?

What is the percentage of hydrogen in nitrogen trihydride

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?