I need help on this chemistry review, specifically this question:

Which of these properties, used alone, would be least useful in identifying most minerals? a. color b. luster c. streak d. density

What is the energy in joules of a mole of photons associated with visible light of wavelength 486 nm?

0.88 moles of n2o5 (g) was placed in a sealed 1.00 l vessel. calculate the equilibrium concentration of n2o5. no2, and o2 and the equilibrium constant after equilibrium has been reached by 65.0% of the n2o5 decomposing.