Which planet in our solar system is closest to the sun? a)jupiter b)earth c)mercury d)saturn

Which of these would be caused by a chemical change? a) the formation of lava. b) sedimantary rock layering over time. c) metamorphic rock forming from igneous. d) metamorphic rock eroding to form sedimentary rock.

What metric units would you use to measure the thickness of a key

If 3 moles of a compound use 24 j of energy in a reaction, what is the a hreaction in j/mol?