If a sample of aluminum oxide ore has a mass of 175 grams and contains 62 grams of aluminum, what is the percent oxygen in
the sample?

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

Asample of tin (ii) chloride has a mass of 0.49 g. after heating, it has a mass of 0.41 g.  what is the percent by mass of water in the hydrate?   %

Astring vibrates with a frequency of 10 hz. why can't a person hear the sound waves produced by the vibrating string, no matter how large the amplitude of the waves? out! this is homework and due tomorrow! you so much!