CH. 6 Chem

-390.3 kJ

Calculate ΔHrxn for the following reaction: CH4(g)+4Cl2(g)→CCl4(g)+4HCl(g) Use the following reactions and given ΔH′s. C(s)+2H2(g)→CH4(g)ΔH=−74.6kJC(s)+2Cl2(g)→CCl4(g)ΔH=−95.7kJH2(g)+Cl2(g)→2HCl(g)ΔH=−184.6kJ

28 g

A 32.7 g iron rod, initially at 22.8 ∘C, is submerged into an unknown mass of water at 63.2 ∘C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 58.7 ∘C. What is the mass of the water? Express your answer to two significant figures and include the appropriate units.

A.2.88×10^9 J B.2.88×10^6 kJ C. 6.88×10^5 Cal

A particular frost-free refrigerator uses about 800 kWh of electrical energy per year. A.Express this amount of energy in joules (J). B.Express this amount of energy in kilojoules (kJ). C. Express this amount of energy in Calories (Cal).

318 kJ

A system absorbs 198 kJ of heat and the surroundings do 120 kJ of work on the system. What is the change in internal energy of the system? Express the internal energy in kilojoules to three significant figures.

-1235 kJ -803 kJ -393.5 kJ -179.2 kJ

A. Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction: C2H5OH(l)+3O2(g)→2CO2(g)+3H2O(g) B.Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction: CH4(g)+2O2(g)→CO2(g)+2H2O(g) C. Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction: C(s)+O2(g)→CO2(g) D. Use standard enthalpies of formation to calculate ΔH∘rxn for the following reaction: CaO(s)+CO2(g)→CaCO3(s)

131.3 kJ

Calculate ΔHrxn for the following reaction: C(s)+H2O(g)→CO(g)+H2(g) Use the following reactions and given ΔH values: C(s)+O2(g)→CO2(g), ΔH= -393.5 kJ 2CO(g)+O2(g)→2CO2(g), ΔH= -566.0 kJ 2H2(g)+O2(g)→2H2O(g), ΔH= -483.6 kJ

A. 363 kJ B. -121 kJ C. -60.5

Consider the following generic reaction: A+2B→C+3D, with ΔH = 121 kJ . Determine the value of ΔH for each of the following related reactions. A= 3A+6B→3C+9D B= C+3D→A+2B C= 12C+32D→12A+B

102816 J

How much heat is required to warm 1.70 kg of sand from 28.0 ∘C to 100.0 ∘C? Express the heat in joules to three significant figures.

26 kJ/mol

Instant cold packs, often used to ice athletic injuries on the field, contain ammonium nitrate and water separated by a thin plastic divider. When the divider is broken, the ammonium nitrate dissolves according to the following endothermic reaction: NH4NO3(s)→NH+4(aq)+NO−3(aq) In order to measure the enthalpy change for this reaction, 1.25 g of NH4NO3 is dissolved in enough water to make 25.0 mL of solution. The initial temperature is 25.8 ∘C and the final temperature (after the solid dissolves) is 21.9 ∘C. Calculate the change in enthalpy for the reaction in kilojoules per mole. (Use 1.0g/mL as the density of the solution and 4.18J/g⋅∘C as the specific heat capacity.) Express your answer to two significant figures and include the appropriate units.

5.32 g

Part complete What mass of natural gas (CH4) must you burn to emit 266 kJ of heat? CH4(g)+2O2(g)→CO2(g)+2H2O(g)ΔH∘rxn=−802.3kJ Express the mass in grams to three significant figures.

41 J

The air in an inflated balloon (defined as the system) is warmed over a toaster and absorbs 120 J of heat. As it expands, it does 79 J of work. What is the change in internal energy for the system, in Joules? Express your answer using two significant figures.

-365.5 kJ

The explosive nitroglycerin (C3H5N3O9) decomposes rapidly upon ignition or sudden impact according to the following balanced equation: 4C3H5N3O9(l)→12CO2(g)+10H2O(g)+6N2(g)+O2(g)ΔH∘rxn=−5678kJ Calculate the standard enthalpy of formation (ΔH∘f) for nitroglycerin.