4. The reaction of 250.0 mL of a 1.00 M hydrochloric acid solution with 250.0 mL of a 1.00 M sodium hydroxide solution was carried out in a constant pressure calorimeter. The total heat capacity of the calorimeter plus solutions was 6.45 kJ/K. The temperature of the calorimeter and solutions increased by 2.11°C. What is AH (in kJ) for the neutralization of 1.00 mol HCl(aq) by NaOH(aq)? A) -54.4 B) -21.2 +12.6 +54.4 E) -12.6

A sample of ethanol, C2H5OH, weighing 2.84 g was burned in an excess of oxygen in a bomb calorimeter. The temperature of the calorimeter rose from 25.00C to 33.73C. If the heat capacity of the calorimeter and contents was 9.63 kJ/C, what is the value of q for burning 1.00 mol of ethanol at constant volume and 25.00C? The reaction is C2H5OH(l)+3O2(g)2CO2(g)+3H2O(l) Is q equal to U or H?

Give the definition of the standard enthalpy of formation for a substance. Write separate reactions for the formation of NaCl, H2O , C6H12O6, and PbSO4 that have H values equal to Hf for each compound.

Ammonium nitrate is an oxidizing agent and can give rise to explosive mixtures. A mixture of 2.00 mol of powdered aluminum and 3.00 mol of ammonium nitrate crystals reacts exothermically yielding nitrogen gas, water vapor, and aluminum oxide. How many grams of the mixture are required to provide 245 kJ of heat? See Appendix C for data.

Under what circumstances is the heat of a process equal to the enthalpy change for the process?

When a 0.740-g sample of trinitrotoluene (TNT), C7H5N2O6, is burned in a bomb calorimeter, the temperature increases from 23.4 C to 26.9 C. The heat capacity of the calorimeter is 534 J/C, and it contains 675 mL of water. How much heat was produced by the combustion of the TNT sample?

A student performing a calorimetry experiment combined 100.0 ml. of 0.50 M HCI and 100.0 ml. of 0.50 M NaOH in a StyrofoamTM cup calorimeter. Both solutions were initially at 20.0 C, but when the two were mixed, the temperature rose to 23.2 C (a) Suppose the experiment is repeated in the same calorimeter but this time using 200 mL of 0.50 M HCl and 200.0 ml of 0.50 M NaOH. WIII the AT observed be greater than, less than, or equal to that in the first experiment, and why? (b) Suppose that the experiment is repeated once again in the same calorimeter, this time using 100 mL of 1.00 M HCI and 100.0 ml. of 1.00 M NaOH. Will the T observed be greater than, less than, or equal to that in the first experiment, and why?

Another reaction that is used to propel rockets is N2O4(l)+2N2H4(l)3N2(g)+4H2O(g) This reaction has the advantage that neither product is toxic, so no dangerous pollution is released. When the reaction consumes 10.0 g liquid N2O4, it releases 124 kJ of heat. (a) Is the sign of the enthalpy change positive or negative? (b) What is the value of H for the chemical equation if it is understood to be written in molar quantities?

When 1.0 g of fructose, C6H12O6(s), a sugar commonly found in fruits, is burned in oxygen in a bomb calorimeter, the temperature of the calorimeter increases by 1.58 C. If the heat capacity of the calorimeter and its contents is 9.90 kJ/C, what is q for this combustion?

9.41 Under what conditions does the enthalpy change equal the heat of a process?