"what is the ph of a 0.160 m ammonia solution"? express your answer numerically to two decimal places.

3.47 x 10⁻⁹.

Explanation:

∵ [OH⁻] = √(Kb)(C).

Kb for ammonia = 1.8 x 10⁻⁵.

∴ [OH⁻] = √(Kb)(C) = √(1.8 x 10⁻⁵)(0.16 M) = 2.88 x 10⁻⁶ M.

∵ [H⁺][OH⁻] = 10⁻¹⁴.

∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(2.88 x 10⁻⁶) = 3.47 x 10⁻⁹ M.

∵ pH = - log[H⁺] = - log(3.47 x 10⁻⁹) = 8.459 ≅ 8.46.

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation:

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.