Which one of the following compounds contains an ion with a 3+ charge? na2o cucl mgcl2 kcl fecl3

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?

Which is true according to the law of conservation of energy

How many moles in .5g of sodium bromide?