Molar mass C₂H₅OH = 46.08 g/mol Moles = 1.20 g / 46.08 g/mol = 0.02604 mol

Assume the density of the solution is the same as water (

Chemsheets Worksheet 2 usually ramps up the difficulty from introductory sheets. It tests three critical skills: precise calculation, unit conversion (Joules to kilojoules), and molar ratio determination.

ΔH_comb = –37.47 kJ / 0.02604 mol = –1439 kJ/mol

A presentation featuring step-by-step solutions for common calorimetry problems, such as heating water or copper, can be found on Course Hero walkthrough for a specific question from that worksheet? Solving a Basic Calorimetry Problem | Chemistry - Study.com

| Mistake | Correction | |---------|-------------| | Using wrong specific heat | Water is 4.18 J/g°C – don’t use 2.01 (ice) or 2.03 (steam) | | Forgetting to convert cm³ to dm³ for moles | 25.0 cm³ = 0.0250 dm³ | | Ignoring calorimeter heat capacity | In bomb calorimetry, always include q_cal = C × ΔT | | Sign of ΔH | Exothermic = negative; Endothermic = positive | | Using total volume, not mass | Always find mass via m = density × volume, especially if density ≠ 1.00 |

Educators appreciate Chemsheets because it systematically builds difficulty. Worksheet 2 typically sits between basic heat calculations (Worksheet 1) and full Hess’s law or bond energy problems (Worksheet 3). By mastering the answers to Worksheet 2, students prove they can:

–1440 kJ/mol (Accepted literature value is –1368 kJ/mol, but calorimeter experiments often yield –1400 to –1450 range.)

While this equation looks simple, Chemsheets challenges you to apply it with precision and pay attention to unit conversions.

q_total = q_water + q_cal = 31.77 kJ + 5.70 kJ = 37.47 kJ