radioactive k has half-life of 20 minutes. If a 40.0 gram sample is allowed to decay 80 minutes, how many grams of isotope will be used.

What is the nature of the ca-cl bond in a molecule of calcium chloride (cacl2) if the electronegativity value of calcium is 1.0 and that of chlorine is 3.16?

This large tectonic plate is bounded on three sides by whats know as the ring of fire. what is the name of this tectonic plate? a) pacific plate b) eurasian plate c) north american plate d) indo- australian plate plz it's science but there's no option for science so i picked chemistry

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