Why can't subscripts be changed in chemical formulas

150.0 grams of asf3 were reacted with 180.0 g of ccl4 to produce ascl3 and ccl2f2. if the actual yield of ccl2f2 was 127 g, what is the percent yield?

Which is a chemical property of iron? a. it forms iron oxide (rust) when exposed to moisture and air. b. it is a gray–black metal that is hard to the touch. c. it has a melting point of 2795°f (1536°c). d. it is a good conductor of heat

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons