4hf(g)+sio2(s)→sif4(g)+2h2o(l)what mass of water (in grams) is produced by the reaction of 67.0 g of sio2 ?

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

The biosphere of the earth is made up of what compound? organic or inorganic?

Question 3(multiple choice worth 4 points) (04.04 lc) what does it mean when an element is reduced? it empties a valance shell, reducing its atomic radius. it gains electrons, reducing its overall charge. it increases electronegativity, reducing its ability to bond. it loses electrons, reducing its electron number.