Consider these reactions, where M represents a generic metal. 1. 2M(s)+6HCl(aq)-2MC13(aq)+3H2(g)AH1=-658.0 kJ 2. HCl(g) HCl(aq) AH2=-74.8 kJ 3. H2(g)+Cl2(g) 2HCl(g) AH3=-1845.0 kJ 4. MC13(s) MC13(aq) AH4=-338.0 kJ Use the given information to determine the enthalpy of the reaction 2M(s)+3C12(g) 2MC13(s)

A piece of lead of mass 121.6 g was heated by an electrical coil. From the resistance of the coil, the current, and the Time the current flowed, it was calculated that 235 J of heat was added to the lead. The temperature of the lead rose from 20.4C to 35.5C. What is the specific heat of the lead?

How much heat is required to raise the temperature of 100. grams of water from 25C near room temperature to 100.C its boiling point? The specific heat of water is approximately 4.2Jperg-K. a.3.2104J b.32J c.4.2104J d.76J

A piece of iron was heated to 95.4C and dropped into a constant-pressure calorimeter containing 284 g of water at 32.2C. The final temperature of the water and iron was 51.9C. Assuming that the calorimeter itself absorbs a negligible amount of heat, what was the mass (in grams) of the piece of iron? The specific heat of iron is 0.449 J/(gC), and the specific heat of water is 4.18 J/(gC).

The equation for the fermentation of glucose to alcohol and carbon dioxide is: C6H12O6(aq) 2C2H5OH(aq) + 2CO2(g) The enthalpy change for the reaction is 67 kJ. Is this reaction exothermic or endothermic? Is energy, in the form of heat, absorbed or evolved as the reaction occurs?

Natural gas companies in the United States use the therm as a unit of energy. One therm is 1105 BTU. (a) How many joules are in one therm? (1J=9.48104BTU) (b) When propane gas, C3H8, is burned in oxygen, CO2 and steam are produced. How many therms of energy are given off by 1.00 mol of propane gas?

Graphite is burned in oxygen to give carbon monoxide and carbon dioxide. If the product mixture is 33% CO and 67% CO2 by mass, what is the heat from the combustion of 1.00 g of graphite?

Enthalpy a A 100.-g sample of water is placed in an insulated container and allowed to come to room temperature at 21C. To heat the water sample to 41C, how much heat must you add to it? b Consider the hypothetical reaction,2X(aq)+Y(l)X2Y(aq)being run in an insulated container that contains 100. g of solution. If the temperature of the solution changes from 21C to 31C, how much heat does the chemical reaction produce? How does this answer compare with that in part a? (You can assume that this solution is so dilute that it has the same heat capacity as pure water.) c If you wanted the temperature of 100. g of this solution to increase from 21C to 51C, how much heat would you have to add to it? (Try to answer this question without using a formula.) d If you had added 0.02 mol of X and 0.01 mol of Y to form the solution in part b, how many moles of X and Y would you need to bring about the temperature change described in part c. e Judging on the basis of your answers so far, what is the enthalpy of the reaction 2X(aq) + Y(l) X2Y(aq)?

Bicycling Describe the energy conversions that occur when a bicyclist coasts down a long grade, then struggles to ascend a steep grade.

A 29.1-mL sample of 1.05 M KOH is mixed with 20.9 mL of 1.07 M HBr in a coffee-cup calorimeter (see Section 6.6 of your text for a description of a coffee-cup calorimeter). The enthalpy of the reaction, written with the lowest whole-number coefficients, is 55.8 kJ. Both solutions are at 21.8C prior to mixing and reacting. What is the final temperature of the reaction mixture? When solving this problem, assume that no heat is lost from the calorimeter to the surroundings, the density of all solutions is 1.00 g/mL, and volumes are additive.