An unknown solid is added to water in a calorimeter. The temperature of the water increases. What does this say about the reaction? A The reaction is exothermic. B The reaction is endothermic. C The reaction has absorbed heat from the solution. D The reaction has released heat to the solution. E Both A and D. If 601 J of heat is available, what is the mass in grams of iron (specific heat = 0.450 *°C) that can be g heated from 22.5°C to 120.0°C?

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)?

A piston performs work of 210. L atm on the surroundings, while the cylinder in which it is placed expands from 10. L to 25 L. At the same time, 45 J of heat is transferred from the surroundings to the system. Against what pressure was the piston working?

Consider the following reaction in the vessel described in Question 57. A(g)+B(g)C(s)For this reaction, E=286 J, the piston moves up and the system absorbs 388 J of heat from its surroundings. (a) Is work done by the system? (b) How much work?

A 110.-g sample of copper (specific heat capacity = 0.20 J/C g) is heated to 82.4C and then placed in a container of water at 22.3C. The final temperature of the water and copper is 24.9C. What is the mass of the water in the container, assuming that all the heat lost by the copper is gained by the water?

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.

How much will the temperature of a cup (180 g) of coffee at 95 C be reduced when a 45 g silver spoon (specific heat 0.24 J/g C) at 25 C is placed in the coffee and the two are allowed to reach the same temperature? Assume that the coffee has the same density and specific heat as water.

How much heat is absorbed by a 44.7-g piece of leadwhen its temperature increases by 65.4°C?

How much would the temperature of 275 g of water increase if 36.5 U of heat were added?

When steam condenses to liquid water, 2.26 kJ of heat is released per gram. The heat from 168 g of steam is used to heat a room containing 6.44 104 g of air (20 ft 12 ft 8 ft). The specific heat of air at normal pressure is 1.015 J/(gC). What is the change in air temperature, assuming the heat from the steam is all absorbed by air?