How many moles of each element are in one mole of Be(OH)2? 1 mole of beryllium, 1 mole of oxygen, 2 moles of hydrogen
1 mole of beryllium, 2 moles of oxygen, 2 moles of hydrogen
2 moles of beryllium, 2 moles of oxygen, 2 moles of hydrogen
2 moles of beryllium, 1 mole of oxygen, 1 moles of hydrogen

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

"hydrogen bonding is the attraction of h atoms in the water molecule (slight + charge) to o atoms in a neighboring water molecule (slight - charge); it is a weak interatomic force. but it is still strong enough to the water molecules "stick" together."

the answer is a! (2.9 x 10^-18 j) hope i could someone. : )