How many moles are in a 18.0 L tank of nitrogen (N2) gas at STP?

The excretory system, need answers for all: )

How does the viscosity of magma change as magma cools?

What rule is used to determine how many covalent bonds an element can form? a. the number of covalent bonds is equal to six c the number of covalent bonds is equal to five minus the group number plus the group number b. the number of covalent bonds is equal to eight d. none of the above minus the group number select the best answer from the choices provided