Help!!! Consider the following reaction: 4Al(s) + 3O2(g) → 2Al2O3(s) It takes 4.05 L of pure oxygen gas at STP to react completely with a certain sample of aluminum. What mass of aluminum reacted?
6.50 g
3.21 g
9.23 g
5.22 g
6.02 g

There are 6.022 x 10^23 atoms of hg in 1 mole of hg. the number of atoms in 4.5 moles of hg can be found by multiplying 4.5 by 6.022 x 10^23 a. 2.7 x 10^24 b. 27 x 10^23 c. 2.71 x10^24 d. 27.099 x 10^23

Design techniques and materials that reduce the negative environmental impact of a structure are referred to as

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?