Question 1
A chemist wishes to calibrate a bomb calorimeter, so she combusts 5.58 g of 4-pentenoic acid, Δ
combustionU = -26.77 kJ g
-1, which causes a temperature change from 23.4 °C to 38.9 °C. What should the chemist report for the value of C
cal?
◦ 6.10 kJ °C
-1◦ 9.64 kJ °C
-1◦ 17.5 kJ °C
-1◦ 7.61 kJ °C
-1◦ 28.7 kJ °C
-1Question 2
A 21.8 g sample of ethanol (C
2H
5OH) is burned in a bomb calorimeter according to the following reaction. If the temperature rises from 25.0 °C to 62.3 °C, determine the heat capacity of the calorimeter. The molar mass of ethanol is 46.07 g mol
-1.
C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g) | DrU = -1235 kJ mol-1 |
◦ 4.99 kJ °C
-1◦ 33.1 kJ °C
-1◦ 63.7 kJ °C
-1◦ 5.65 kJ °C
-1◦ 15.7 kJ °C
-1