Molality is defined as the number of moles of solute in 1 kg of solvent.
molality of solution to be prepared is 0.50 molal
this means that in 1000 g of water there should be 0.50 mol of NaCl
if 1000 g of water should contain - 0.50 mol
then 750.0 g of water requires - 0.50 mol/kg x 0.750 kg = 0.375 mol
mass of NaCl in 0.375 mol - 58.5 g/mol x 0.375 mol = 21.9 g
therefore a mass of 21.9 g of NaCl is required
106.4 is going to be your answer
A - its condensation and gas particles have a higher kinetic energy
Answer: 55.56 moles of MgO
Explanation:
1 mole = avogadro number
if 6.21x10^25 atoms then molecules of MgO (equal numbers of Mg and O atoms)
= 0.5*6.21x10^25 = 3.105 molecules of MgO
So moles of MgO = 0.5*6.21*10^25/avogadro number = 55.56
Answer: D
Explanation:
Chlorine is in group 7 or (VII) in Roman numerals, which means it has 7 balance electrons. It only needs one electron to become stable, hence it is next to the noble gases
