Which coefficients balance this equation?
_ch4 + _o2 -> _co2 + _h2o
a. 1, 1, 1, 1
b. 1, 1, 2, 1
c. 1, 2, 1, 2
d. 2, 1, 2, 1

Can someone me with questions 15 to 17 plz.

Aradio signal from a gps satellite take only about 0.067 seconds to reach a gps reciever. if the speed of light is about 300,000km/s, then approximately how far away is the reciever from from the satellite?

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?