General Chemistry Answers

volume of distilled water needed to add to 50 cm³ of 0.2 mol dm³ sodium thiosulphate solution, Na2S2O; so that a 0.025 mol dm² sodium thiosulphate solution, Na2S₂O3 is produced.

List the IMFAs present in the following molecules and

RANK their boiling points solely based on the IMFAs.

Molecule List the IMFAs present Boiling Point Ranking

(1 – highest BP,

5 – lowest BP)

SO3

ICl3

CH3F

CCl3Br

CCl3OH

If 3.65g of butane is burned underneath a cup holding 1.00 L of water at 21.0 oC, what will the final temperature of the water be (Hcomg = -3325kJ/mol)?

Instant hot packs work by crystallizing sodium acetate (NaCH3COO). The molar enthalpy of crystallization for sodium acetate is -56.7 kJ/mol. How many grams of sodium acetate are needed to warm 125.0 mL of water from 21.0 oC to 35.4oC?

When 25.0 mL of 0.25mol/L LiOH and 25.0 mL of 0.25 mol/L HCl are mixed together, the temperature warms 15.8 oC. What is the molar enthalpy of neutralization for LiOH?

When 2.35g Mg(OH)2 is added to 250.0 mL of water, the temperature of the water raises from 20.5 oC to 36.0 oC. Calculate the molar enthalpy of solution.

Use the following thermodynamic data at 298 K to determine the equilibrium constant at this temperature for the reaction of iron in steam to form hydrogen and iron(III) oxide.

2Fe(s) + 3H₂O(g)   3H₂(g) + Fe₂O₃(s)

Substance: ΔH°_f (kJ/mol): ΔG°_f (kJ/mol): S°(J/K·mol)

Fe(s): 0: 0: 27

H₂O(g): -242: -229: 189

H₂(g): -0: -0: 131

Fe₂O₃(s): -824: -742: 87

a)1.8 x 10^-3

b)1.58 x 10²²

c)4.36 x 10^-9

d)4.36 x 10⁹

Use the given data at 298 K to calculate ΔG° for the reaction

CH₄(g) + 2H₂S(g) → CS₂(g) + 4H₂(g)

Substance: ΔH°_f (kJ/mol): S°(J/K·mol)

CH₄(g): -75: 186

H₂S(g): -21: 206

CS₂(g): 90: 151

H₂(g): 0: 131

a)184 kJ

b)5.49 x 10⁴kJ

c)262 kJ

d)5.53 x 10⁴ kJ