Question

PLEASE HELP I NEED THE ANSWERS WITH THE WORK ITS WORTH 50 POINTS!!!!! 1. How much energy would be required to melt 15.0 g of ice at 0 oC? ΔHfus= 6.00 kJ/mol 2. How many moles of ice at 0 oC could be melted with the addition of 750 KJ of energy? ΔHfus= 6.00 kJ/mol 3. How much energy would it take to boil 36.0 g of water at 100 oC? ΔHvap= 40.7 kJ/mol 4. How many grams of steam could be condensed at 100 o C with the removal of 307 kJ of energy? ΔHvap= 40.7 kJ/mol 5. How much energy is needed to make 254 g of iodine melt? ΔHfus= 7.76 kJ/mol 6. How much energy is needed to make 4.24 g of lead melt? ΔHfus= 4.77 kJ/mol

Answer 1

Answer:

1) 5 kJ

2) 125 moles

3) 81.33 kJ

4) 135.9 grams

5) 15.165 kJ

6) 97.6 J

Explanation:

1) Molar mass of ice (water) = 18.015 g/mol

Number of moles, n, of ice = mass/(molar mass) = 15/18.015 = 0.833 moles

ΔHfus = 6.00 kJ/mol

Energy required, E = ΔHfus × n = 0.833 × 6 = 4.996 ≈ 5 kJ

2) Number of moles of ice that can be melted by E = 750 kJ is given by the equation;

n = E/(ΔHfus) = 750/6 = 125 moles

3) Given that ΔHvap = 40.7 kJ/mol, we have;

Number of moles of water, n = 36/18.015 = 1.998 ≈ 2 moles

Heat required = ΔHvap × n = 40.7 × 2 = 81.33kJ

4) Given that heat removed, ΔH= 307 kJ, we have;

n = ΔH/ΔHvap = 307/40.7 = 7.543 moles

Mass of water = Number of moles × Molar mass = 7.543 × 18.015 = 135.9 grams

5) Energy required, E for iodine to melt = Number of moles of iodine × ΔHfus of iodine

Number of moles of iodine = Mass of iodine/(Molar mass of iodine)

Number of moles of iodine = 248/126.9 = 1.954 moles

Energy required, E for iodine to melt = 1.954 × 7.76  = 15.165 kJ

6) Energy required, E for 4.24 g of lead to melt = Number of moles of lead × ΔHfus of lead

Number of moles of lead= Mass of lead/(Molar mass of lead)

Number of moles of iodine = 4.24/207.2 = 0.0205 moles

Energy required, E for iodine to melt = 0.0205 × 4.77 = 9.76 × 10⁻² kJ = 97.6 J.