Concept explainers
Used in welding metals, the reaction of acetylene with oxygen has ΔH° = −1256.2 kJ:
How much PV work is done in kilojoules and what is the value of ΔE in kilojoules for the reaction of 6.50 g of acetylene at atmospheric pressure if the volume change is −2.80 L?
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General Chemistry: Atoms First
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- When 1.000 g of gaseous butane, C4H10, is burned at 25C and 1.00 atm pressure, H2O(l) and CO2(g) are formed with the evolution of 49.50 kJ of heat. a Calculate the molar enthalpy of formation of butane. (Use enthalpy of formation data for H2O and CO2.) b Gf of butane is 17.2 kJ/mol. What is G for the combustion of 1 mol butane? c From a and b, calculate S for the combustion of 1 mol butane.arrow_forwardThree gas-phase reactions were run in a constant-pressure piston apparatus as shown in the following illustration. For each reaction, give the balanced reaction and predict the sign of w (the work done) for the reaction. . If just the balanced reactions were given, how could you predict the sign of w for a reaction?arrow_forwardA 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?arrow_forward
- Gasohol, a mixture of gasoline and ethanol, C2H5OH, is used as automobile fuel. The alcohol releases energy in a combustion reaction with O2. C2H5OH(l)+3O2(g)2CO2(g)+3H2O(l) If 0.115 g ethanol evolves 3.62 kJ when burned at constant pressure, calculate the combustion enthalpy for ethanol.arrow_forwardNitrogen gas reacts with hydrogen gas to form ammonia gas .Consider the reaction between nitrogen and hydrogen as depicted below: a. Draw what the container will look like after the reaction has gone to completion. Assume a constant pressure of 1 atm. b. Is the sign of work positive or negative, or is the value of work equal to zero for the reaction? Explain your answer.arrow_forwardNiagara Falls has a height of 167 ft (American Falls). What is the potential energy in joules of 1.00 lb of water at the top of the falls if we take water at the bottom to have a potential energy of zero? What would be the speed of this water at the bottom of the falls if we neglect friction during the descent of the water?arrow_forward
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