Calculate the enthalpy change that occurs when 1.00 kg of acetone condenses at its boiling point (329.4 K). The standard enthalpy of vaporization of acetone is 29.1 kJ · mol-1 .

1.) −501 kJ
2.) −29.1 kJ
3.) +501 kJ
4.) +29.1 kJ
5.) −2.91 × 104 kJ

Option 1 is correct.

ΔH for the condensation of 1 kg of Acetone is - 501 KJ.

Explanation:

Molar mass of acetone = 58.08 g/mol

Number of moles of acetone that condenses = mass/molar mass = 1000/58.08 = 17.22 moles

1 mole of Acetone vaporizer with an enthalpy change of 29.1 KJ.

1 mole of Acetone will condense with an enthalpy change of - 29.1 KJ (since condensation is the exact reverse of vaporization)

That is, vaporization is given by,

Acetone(l) > Acetone(g) ΔH = 29.1 KJ

Then condensation will be given by,

Acetone(g) > Acetone(l) ΔH = -29.1 KJ

So,

1 mole of Acetone will condense with an enthalpy change of - 29.1 KJ

17.22 moles of Acetone will condense with an enthalpy change of 17.22 × - 29.1 KJ = - 501 KJ.

The first option is correct.

1.) -501 kJ.

Explanation:

The enthalpy of vaporization is defined as the amount of energy that must be added to a liquid substance, to transform a quantity of that substance into a gas.

ΔHvap = 29.1 kJ/mol

Δq = n * ΔHvap

Where,

n = number of moles

ΔHvap = standard enthalpy of vaporization

Δq = enthalpy change of vaporization

Molar mass of acetone, C3H6O = (3*12) + (6*1) + (1*16)

= 58 g/mol

Number of moles = mass/molar mass

= 1000/58

= 17.2412 mol.

Δq = 17.2412 * 29.1

= +501.7 kJ.

Δq = 501 kJ is required to be added to evaporate it so Δq = - 501 kJ is required to condense it

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: