16. How many minutes would it take a radio signal from Earth, traveling at the speed of light (3.00x108 m/s), to reach Mars, a distance of 4.8x107 miles. (1 mi = 1.609 km)

18. use the activity series to predict whether the following synthesis reaction will occur. write the chemical equations for the reaction if it's predicted to occur. (s) + o2(g) -> *note: it is possible.*

Evaluate this exponential expression,8. (2 + 3)2 – 42

Which electron configuration represents the electrons in an atom of sodium in the ground state at stp