In the late eighteenth century Priestley prepared ammonia by reacting HNO3(g) with hydrogen gas. The thermodynamic equation for the reaction is HNO3(g) + 4H2(g) → NH3(g) + 3H2O(g) ΔH = –637 kJ
Calculate the amount of energy released when one mole of hydrogen gas reacts. Consider this to be a positive value.

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.

Consider the following unbalanced equation for the combustion of hexane: αc6h14(g)+βo2(g)→γco2(g)+δh2o(g) part a balance the equation. give your answer as an ordered set of numbers α, β, γ, use the least possible integers for the coefficients. α α , β, γ, δ = nothing request answer part b determine how many moles of o2 are required to react completely with 5.6 moles c6h14. express your answer using two significant figures. n n = nothing mol request answer provide feedback

Akno3 solution containing 51 g of kno3 per 100.0 g of water is cooled from 40 ∘c to 0 ∘c. what will happen during cooling?