Formula: molality, m = n solute / kg solvent
n solute = # of moles of solute = mass(g) / molar mass
Molar mass of Mg Br2 = 184.11 g/mol
m = [46g / 184.11 g/mol] / 0.5 kg = 0.50 mol/kg
Answer: 15.0 moles of
are formed from 30.0 mol of 
Explanation:
The balanced chemical reaction is :
According to stoichiometry :
2 moles of
give = 1 mole of 
Thus 30.0 moles of
will give =
of 
Thus 15.0 moles of
are formed from 30.0 mol of 
Answer:
D
Explanation:
Just look at the groups and their tendencies. Or look at their electron configurations. You will notice that calcium has 2 valence electrons and bromine has 7 valence electrons.
Halogens have the most valence electrons possible without completing a shell (8 would be needed for that)
One candela per steradian is termed a lumen, which is the measure of light intensity people are most familiar with One foot candle is equivalent to one lumen per square foot