Please help lol (look at photo)

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

How much would the freezing point of water decrease if 4 mol of sugar were added to 1 kg of water(k=1.86 c/mol/kg for water and i=1 for sugar

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?