Asubstance is composed of only one kind of atom and can't be separated into simpler substances or converted into another substance by chemical processes. under which category would you classify this substance?

Can you guys me with question no. 5!

Which of the following represents the ester functional group? a. -coo- b. -cho c. -cooh d. c=o

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