Which of the following reactions is correctly balanced? 3 Ca + 1 N2 → Ca3N2
O 2 P2 + 3 H2 → 2 PH3
O 2 HgBr → 1 Hg + 1 Br2
O 2 Sr + 102 — 1 sro

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?

The same side of the moon always faces earth because the

Choose all the answers that apply. fluorine (f) has an atomic number of 9 and an atomic weight of 18.99. fluorine has a. 9 protons b. 10 neutrons c. 18 electrons d. an atomic mass of 19 e. at least one isotope