1) the heat of combustion for the gases hydrogen, methane and ethane are −285.8, −890.4 and −1559.9 kj/mol respectively at 298k.
equation 1 h2 + 1⁄2o2 > h2o δh = −285.8 kj
equation 2 ch4 + 2o2 > co2 + 2h2o δh = −890.4 kj
equation 3 c2h6 + 7⁄2o2 > 2co2 + 3h2o δh = −1559.9 kj

use the above equations to calculate (at the same temperature) the heat of reaction for the following reaction:
2ch4(g) > c2h6(g) + h2(g)
solution:

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.

Compare and contrast solutions and suspensions

Astable electron arrangement for an atom is one that does not easily change. how is this arrangement arrived at? a. valence electrons are transferred or shared to create a full outer shell of electrons. b. valence electrons are discarded into space to create a full outer shell of electrons. c. protons (positive charge) pair with valence electrons (negative charge) to create a strong bond. d. outer shells with valence electrons are transferred or shared.