Problem 76E
Enthalpies of Formation (Section)
Calcium carbide (CaC2) reacts with water to form acetylene (C2H2) and Ca(OH)2. From the following enthalpy of reaction data and data in Appendix C, calculate ΔHf° for CaC2(s):
CaC2(s) + 2 H2O(l) → Ca1OH22(s) + C2H2(g)
ΔH° = –127.2 kJ
Chapter 1 Notes Data Communications Networks Data Communications—the movement of computer information from one point to another by meals of electrical or optical transmission systems o Such systems called data communications networks o Telecommunications—broader term; includes transmission of voice and video as well as data and usually implies longer distances. Components of a Network Three basic hardware components for a data communications network: o Server—personal computer, mainframe o Client—personal computer, terminal o Circuit—cable, modem Server—stores data or software that can be accessed by the clients. o File Server—stores data and software that can be used by computers on the network o Print Server—connected to a printer; manages all printing requests from the clients on the network o Web Server—stores documents and graphics that can be accessed from any Web browser, such as Internet Explorer. Can respond to requests form computers on this network or any computer on the Internet o Servers are usually personal computers but may be minicomputers or mainframes. Client—the input-output hardware device at the user’s end of a communication circuit o Provides the user with access to the network and the data and software on the server Circuit—the pathway through which the messages travel o Typically a copper wire, although fiber-optic cable and wireless
