Match these items.

1. umbra of moon touches the Earth
total lunar eclipse
2. penumbra of moon touches the Earth
partial lunar eclipse
3. umbra of Earth touches the moon
total solar eclipse
4. penumbra of Earth touches the moon
partial solar eclipse

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)

Why does earth rotate? because earth is formed from cold gases collapsing due to gravity because the matter in the nebula that formed earth was spinning because earth forms more than 99% of the mass of the solar system because the hydrogen atoms inside the nebula fused to form helium

How many moles of oxygen gas are produced from the decomposition of six moles of potassium chlorate