Question: Determine the enthalpy of formation of liquid hydrogen peroxide, H2O2, at 25°C from the following thermochemical equations: Since the equation is not given, you have to write the balanced equation to form I mol H:O: from elements! H2 (g) + ½ O2 (g)→ H20 (g) 2H (g) + ½ O2 (g) → H20 (g) 2H (g) + 2 0 (g) O2 (g) H2O2 (I) H2O2 (g) AH° = -241.82 kJ/mol AH° = -926.92 kJ/mol AH° = -1070.60 kJ/mol AH° = -498.34 kJ/mol - H2O2 (g) 20 (g) → AH° = +52.46 kJ/mol [+60.38 kJ mot')

Consider the hypothetical thermochemical equation 3 A + B → 2 C for which ΔH = 63.1 kJ/mol. If the reaction absorbs 345 kJ of heat, how many moles of C would be produced?

What is the enthalpy change for the first reaction? CH4(g) + 1/2O2(g) → CH3OH(g) ΔH =  CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)  ΔH = -806.5 CH3OH(l) + 3/2 O2 → CO2(g) + 2H2O(g)  ΔH = -676.7

What is the enthalpy change when  2.00 mol of oxygen (O2) react? C12H22O11(s)   + 12 O2(g) →    12 CO2(g)  +    11 H2O(l)        ΔH = -5644 kJ

Q/ For each compound below, write the balanced chemical equation that represents its enthalpy of formation (ΔHf ° ). a) Li2CO3(s) b) CH3CH2OH(l)

(please type answer no write by hand)

A 3.59°C increase in temperature occurs when a 0.232 g sample of benzoic acid (C7H6O2) is combusted in a bomb calorimeter. A 1.81 °C increase in temperature occurs when a 0.303 g sample of citric acid (C6H8O7) is combusted in the same bomb calorimeter. The heat of combustion of benzoic acid is -26.37 kJ/g. What is the molar heat of combustion of citric acid? Reminder: Any heats of combustion will be negative since these are exothermic reactions.

The flame in a torch used to cut metal is produced by burning acetylene (C2H2)(26.04 g/mol) in pure oxygen. Assuming the combustion of 1 mole of acetylene releases 1251 kJ of heat, what mass of acetylene is needed to cut through a piece of steel if the process requires 22.5  × 104 kJ of heat?                                            2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(g) ΔH = –2502 kJ

Consider the hypothetical thermochemical equation:  3 A + B ----> 2 C for which delta H = 62.1 kJ/mol. Which one of the following reactions would have an enthalpy change of -2xdelta H? Here, delta H refers to the enthalpy change of the original reaction.

（1）Consider the reaction: 2A (g) + 3 B (g) → 2 C (g)     ΔHrxn = +254.3 kJ What will be the enthalpy change (in kJ) if 0.471 mol B reacts in excess A?   （2）Consider the reaction: C (s) + O2 (g) → CO2 (g)     ΔHrxn = -393.5 kJ What mass of carbon (in g) must be reacted via this mechanism to release 581.2 kJ of heat?