How many grams of o2(g) are needed to completely burn 48.5 g of c3h8(g)?

Ionic compounds are made of ions, and yet the overall charge of an ionic compound is neutral. why?

If we compare and contrast electromagnetic waves with sound waves, all but one statement is true. that is a) sound waves require a medium to travel while electromagnetic waves do not. b) electromagnetic waves can travel through the vacuum of space while sound waves cannot. c) electromagnetic waves must have a medium in which to travel, but sound waves can travel anywhere. eliminate d) sound waves must bounce off of matter in order to travel while electromagnetic waves do not require matter to be present.

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.