1. The compound calcium carbide, CaC, is made by reacting calcium carbonate with carbon at a
very high temperature. The unbalanced equation for the reaction is:
CaCO +
c
+
CaC +
CO.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).