Concept explainers
Use the heat equation to calculate the energy, in joules and calories, for each of the following (see TABLE3.11):
a. to heat 25.0 g of water from 12.5 °C to 25.7 °C
b. to heat 38.0 g of copper from 122 °C to 246 °C
c. lost when 15.0 g of ethanol, C2H6O, cools from 60.5 °C to −42.0 °C
d. lost when 125 g of iron cools from 118 °C to 55 °C
TABLE 3.11 Specific Heats for Some Substance
Substance |
|
|
Elements | ||
Aluminum, Al(s) | 0.214 | 0.897 |
Copper, Cu(s) | 0.0920 | 0.385 |
Gold, Au(s) | 0.0308 | 0.129 |
Iron, Fe(s) | 0.108 | 0.452 |
Silver, Ag(s) | 0.0562 | 0.235 |
Titanium, Ti(s) | 0.125 | 0.523 |
Compounds | ||
Ammonia, NH3(g) | 0.488 | 2.04 |
Ethanol, C2H6O(?) | 0.588 | 2.46 |
Sodium chloride, NaCl(s) | 0.207 | 0.864 |
Water, H2O(?) | 1.00 | 4.184 |
Water, H2O(s) | 0.485 | 2.03 |
Trending nowThis is a popular solution!
Chapter 3 Solutions
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
- 9.55 Hydrogen gas will react with either acetylene or ethylene gas. The thermochemical equations for these reactions are provided below. Write the thermochemical equation for the conversion of acetylene into ethylene by hydrogen gas. C2H2(g)+2H2(g)C2H6 H= -311 kJ C2H4(g)+H2(g)C2H6 H = -136 kJarrow_forwardSmall amounts of oxygen gas can be prepared in the laboratory by decomposing potassium chlorate with heat. A by-product of the decomposition is potassium chloride. When one mole of potassium chlorate decomposes, 44.7 kJ are evolved. (a) Write a balanced thermochemical equation for the decomposition of one mole of potassium chlorate. (b) Is the reaction exothermic? (c) Draw an energy diagram showing the path of this reaction. (Figure 8.6 is an example of such an energy diagram.) (d) What is H when 3.00 g of potassium chlorate decompose? (e) How many grams of potassium chlorate need to be decomposed to liberate fifteen kilojoules of heat?arrow_forwardThe overall reaction in a commercial heat pack can be represented as 4Fe(s)+3O2(g)2Fe2O3(s)H=1652KJ a. How much heat is released when 4.00 moles of iron are reacted with excess O2? b. How much heat is released when 1.00 mole of Fe2O3 is produced? c. How much heat is released when 1.00 g iron is reacted with excess O2? d. How much heat is released when 10.0 g Fe and 2.00 g O2 are reacted?arrow_forward
- Hydrogen cyanide is a highly poisonous, volatile liquid. It can be prepared by the reaction CH4(g)+NH3(g)HCN(g)+3H2(g) What is the heat of reaction at constant pressure? Use the following thermochemical equations: N2(g)+3H2(g)2NH3(g);H=91.8kJC(graphite)+2H2(g)CH4(g);H=74.9kJ12H2(g)+C(graphite)+12N2(g)HCN(g);H=135.1kJarrow_forwardThe Group 2A carbonates decompose when heated. For example, BaCO3(s)BaO(s)+CO2(g) Use enthalpies of formation (see Appendix C) and calculate the heat required to decompose 6.50 g of barium carbonate.arrow_forwardA soluble salt, MX2, is added to water in a beaker. The equation for the dissolving of the salt is: MX2(s)M2+(aq)+2X(aq);H0 a Immediately after the salt dissolves, is the solution warmer or colder? b Indicate the direction of heat flow, in or out of the beaker, while the salt dissolves. c After the salt dissolves and the water returns to room temperature, what is the value of q for the system?arrow_forward
- When one mole of calcium carbonate reacts with ammonia, solid calcium cyanamide, CaCN2, and liquid water are formed. The reaction absorbs 90.1 kJ of heat. (a) Write a balanced thermochemical equation for the reaction. (b) Using Table 8.3, calculate Hf for calcium cyanamide.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_forwardA 15.5-g piece of chromium, heated to 100.0 C, is dropped into 55.5 g of water at 16.5 C. The final temperature of the metal and the water is 18.9 C. What is the specific heat capacity of chromium? (Assume no energy is lost to the container or to the surrounding air.)arrow_forward
- The initial temperature of a 344-g sample of iron is 18.2 C. If the sample absorbs 2.25 kJ of energy as heat, what is its final temperature?arrow_forwardAn ice calorimeter can be used to determine the specific heat capacity of a metal. A piece of hot metal is dropped onto a weighed quantity of ice. The energy transferred from the metal to the ice can be determined from the amount of ice melted. Suppose you heated a 50.0-g piece of silver to 99.8 C and then dropped it onto ice. When the metals temperature had dropped to 0.0 C. it is found that 3.54 g of ice had melted. What is the specific heat capacity of silver?arrow_forwardWhen a 0.740-g sample of trinitrotoluene (TNT), C7H5N2O6, is burned in a bomb calorimeter, the temperature increases from 23.4 C to 26.9 C. The heat capacity of the calorimeter is 534 J/C, and it contains 675 mL of water. How much heat was produced by the combustion of the TNT sample?arrow_forward
- Chemistry for Engineering StudentsChemistryISBN:9781337398909Author:Lawrence S. Brown, Tom HolmePublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry by OpenStax (2015-05-04)ChemistryISBN:9781938168390Author:Klaus Theopold, Richard H Langley, Paul Flowers, William R. Robinson, Mark BlaserPublisher:OpenStax
- Chemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage Learning