Find the mass of 0.89 moles of magnesium chloride, mgcl2

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

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

the answer is c i took the test