Someone pls help me I will make you brain

What happened in 2012 and how does it illustrate the importance of understanding the sun and how it works?

Frictional forces acting on an object are often converted into energy, which causes the temperature of the object to rise slightly.

Given the following at 25c calculate delta hf for hcn (g) at 25c. 2nh3 (g) +3o2 (g) + 2ch4 (g) > 2hcn (g) + 6h2o (g) delta h rxn= -870.8 kj. delta hf=-80.3 kj/mol for nh3 (g), -74.6 kj/mol for ch4, and -241.8 kj/mol for h2o (g)