Which two atoms are isotopes of each other? OA. 37si and 25 mg
OB.
24
24
12Mg and 13AI
25
oc. 2, Mg and
OD. 7. Na and 2 Mg
12 Mg

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.