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Classify each of the following as exothermic or endothermic, and give the
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Chapter 9 Solutions
Basic Chemistry
- Classify each process as exothermic or endothermic. (a) ice melts (b) gasoline burns (c) steam condenses (d) reactants products, H = 50 kJarrow_forwardThe temperature of the cooling water as it leaves the hot engine of an automobile is 240 F. After it passes through the radiator it has a temperature of 175 F. Calculate the amount of heat transferred from the engine to the surroundings by one gallon of water with a specific heat of 4.184 J/g oC.arrow_forwardNitrogen monoxide, a gas recently found to be involved in a wide range of biological processes, reacts with oxygen to give brown NO2 gas. 2 NO(g) + O2(g) NO2(g)rH = 114.1 kJ/mol-rxn Is this reaction endothermic or exothermic? What is the enthalpy change if 1.25 g of NO is converted completely to NO2?arrow_forward
- Quinone is an important type of molecule that is involved in photosynthesis. The transport of electrons mediated by quinone in certain enzymes allows plants to take water, carbondioxide, and the energy of sunlight to create glucose. A 0.1964-g sample of quinone (C6H4O2) is burned in a bomb calorimeter with a heat capacity of 1.56 kJ/C. The temperature of the calorimeter increases by 3.2C. Calculate the energy of combustion of quinone per gram and per mole.arrow_forwardWhen calcium carbonate, CaCO3 (the major constituent of limestone and seashells), is heated, it decomposes to calcium oxide (quicklime). CaCO3(s)CaO(s)+CO2(g);H=177.9kJ How much heat is required to decompose 21.3 g of calcium carbonate?arrow_forwardSalicylic acid, C7H6O3, is one of the starting materials in the manufacture of aspirin. When 1.00 g of salicylic acid burns in a bomb calorimeter, the temperature of the bomb and water goes from 23.11C to 28.91C. The calorimeter and water absorb 21.9 kJ of heat. How much heat is given off when one mole of salicylic acid burns?arrow_forward
- Determine whether the statements given below are true or false. Consider an endothermic process taking place in a beaker at room temperature. (a) Heat flows from the surroundings to the system. (b) The beaker is cold to the touch. (c) The pressure of the system decreases. (d) The value of q for the system is positive.arrow_forwardThe combustion of 1.00 mol liquid methyl alcohol (CH3OH) in excess oxygen is exothermic, giving 727 kJ of heat. (a) Write the thermochemical equation for this reaction. (b) Calculate the enthalpy change that accompanies the burning 10.0 g methanol. (c) Compare this with the amount of heat produced by 10.0 g octane, C8H18, a component of gasoline (see Exercise 5.41).arrow_forwardSulfur dioxide gas reacts with oxygen, O2(g), to produce SO3(g). This reaction releases 99.0 kJ of heat (at constant pressure) for each mole of sulfur dioxide that reacts. Write the thermochemical equation for the reaction of 2 mol of sulfur dioxide, and then also for the decomposition of 3 mol of sulfur trioxide gas into oxygen gas and sulfur dioxide gas. Do you need any other information to answer either question?arrow_forward
- In a calorimetric experiment, 6.48 g of lithium hydroxide, LiOH, was dissolved in water. The temperature of the calorimeter rose from 25.00C to 36.66C. What is H for the solution process? LiOH(s)Li(aq)+OH(aq) The heat capacity of the calorimeter and its contents is 547 J/C.arrow_forwardWhich of the following substances have an enthalpy of formation equal to zero? a. Cl2(g) b. H2(g) c. N2(l) d. Cl(g)arrow_forwardAn iron skillet weighing 1.63 kg is heated on a stove to 178C. Suppose the skillet is cooled to room temperature, 21C. How much heat energy (in joules) must be removed to affect this cooling? The specific heat of iron is 0.449 J/(gC).arrow_forward
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