What type of energy transformation is taking place when natural gas is used to heat water?
a. chemical energy to thermal energy
b. thermal energy into mechanical energy
c. mechanical energy into electromagnet energy
d. electromagnet energy into chemical energy

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?

16. why must the number of electrons lost equal the number of electrons gained in every redox reaction? use 3 – 4 sentences in your own words to address this question. 18. what type of radiation is emitted when chromium-51 decays into manganese-51? show the nuclear equation that leads you to this answer. 19. a radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. what was the identity of the original nucleus? show the nuclear equation that leads you to this answer.

Aconcentrated solution of ammonia is 14.8m and has a density of 0.899g/l. what is the concentration of ammonia in this solution in weight percent (%w/w)?