Question: 0.25 g of ethanol (C₂H₅OH) is burned, heating 150 g of water from 20.0°C to 45.5°C. Calculate ΔH_combustion in kJ/mol.
Step 1 – Heat gained by water
q = m × c × ΔT = 150 × 4.18 × (45.5 – 20.0)
q = 150 × 4.18 × 25.5
q = 15,988.5 J = 16.0 kJ
Step 2 – Moles of ethanol burned
Molar mass C₂H₅OH = (2×12) + (6×1) + 16 = 46 g/mol
Moles = 0.25 / 46 = 0.005434 mol
Step 3 – Heat per mole
q_per_mol = 16.0 kJ / 0.005434 mol = 2944 kJ/mol
Step 4 – Sign
Temp increased → exothermic → negative
Final answer: –2940 kJ/mol (3 sig figs)
Data:
50 cm³ 1.0 M HCl + 50 cm³ 1.0 M NaOH
Initial temp = 21.0 °C
Final temp = 27.8 °C
Assume density = 1.00 g/cm³, ( c = 4.18 \ \textJ g^-1\textK^-1 ) calorimetry worksheet 2 answers chemsheets
Step 1 – Total mass of solution
[
m = 50 + 50 = 100 \ \textg
]
Step 2 – Heat released
[
q = 100 \times 4.18 \times (27.8 - 21.0)
]
[
q = 100 \times 4.18 \times 6.8 = 2842.4 \ \textJ \approx 2.84 \ \textkJ
]
Step 3 – Moles of water formed
Limiting: both 0.050 mol (since 1:1 reaction)
[
n = 0.050 \ \textmol
]
Step 4 – Molar enthalpy of neutralization
[
\Delta H = -\frac2.840.050 = -56.8 \ \textkJ mol^-1
]
Answer: (-56.8 \ \textkJ mol^-1)
(Expected ~ –57 kJ mol⁻¹) Question: 0
Don’t just copy answers—use them to find your weak spots. If you got a sign wrong on Q1, that’s an easy fix. If your moles were off, practice molar mass calculations. Calorimetry is repetitive by design; by the third question, the process should feel automatic.
Have you tried the worksheet and hit a wall? Drop the question number in the comments—I’ll walk you through it.
Happy calculating (and stay cool). 🔥❄️
To provide a comprehensive essay that could relate to "calorimetry worksheet 2 answers chemsheets," let's break down the concept of calorimetry and the type of problems one might encounter in a worksheet related to this topic. Calorimetry is a crucial concept in chemistry that involves the measurement of heat changes during chemical reactions or physical transformations.
Even with the correct calorimetry worksheet 2 answers chemsheets, students lose marks due to: Don’t just copy answers—use them to find your weak spots
There are several types of calorimeters and calorimetric techniques, including:
Typical problem from Chemsheets (A-Level style): A calorimeter has a heat capacity of 50.0 J/°C. It contains 150.0 g of water. A reaction causes the temperature to rise from 22.0°C to 29.5°C. Calculate the total heat released.
Step-by-step answer:
Answer: Total heat released = 5.08 kJ (Note: If calculating ΔH of reaction, divide by moles of reactant).