Find the % by mass of oxygen if a compound is decomposed by an electric current giving 19.98 g O and 2.52 g H.

100mg magnesium reacts with 20ml of 1.0m hcl

Rocks, as they are compressed, begin forming mountains above the earth's surface when two continental plates converge. the continental crust increases in depth as the mountains grow above. the himalayan mountains formed at a convergent plate boundary in this manner. the rocks are smashed together causing them to due to the intense heat and pressure from the colliding plates and eventually forming rock. a) melt; igneous b) layer; sedimentary c) recrystallize; metamorphic d) melt into the earth's interior; metamorphic

Is 9 correct? and can someone me with 10? it’s due tomorrow, you