Question

HELP PLEASE I need help with these 2 chem questions asap i would gladly appreciate it :)

Answer 1

10) You need to find the atomic mass of every element, which you can get from any periodic table.

a) 6.02x10^23 atoms of Mg

Atomic mass of Mg = 24.3 g/mol

# of mols = 6.02 x 10^23 atoms / 6.02 x 10^23 atoms/mol = 1 mol

mass = 1 mol x 24.3 g/mol = 24.3 g

b) 3.01x10^23 formula units of Ca Cl2

Atomic masses

Ca: 40 g/mol
Cl: 35.5 g/mol

Formula mass: 40g/mol + 2x 35.5g/mol = 111 g/mol

# of mols = 3.01 x 10^23 / 6.02 x 10^23 = 0.5 mol

mass = 0.5 mol x 111 g/mol = 55.5 g


c) 12.4 x 10^15 molecules of CH2O

formula mass = 12 g/ mol + 2 g/mol + 16 g/mol = 30 g/mol
# of mols

mass = [12.4 x 10^15 / 6.02 x 10^23]mol x 30 g/mol  = 2.1 x 10 ^(-8) g

3)

a) The polar solute is dissolved in water  which is a polar solvent, while the non polar solute is not dissolved in water. This is a  rule in chemistry: polar solvents dissovle polar soultes and non polar solvents dissolve non polar soluted.

The extremes of the polar molecules are easily solvated by the water molecules.

b) KI is an ionic compound, which implies that it will ioinize (separare in iones) in water, being in this way be dissolved, while the CO2, which is no polar, will not be easily dissolved in water under normal conditions