Some societies use Oxford Academic personal accounts to provide access to their members. If you do not have a society account or have forgotten your username or password, please contact your society. Do not use an Oxford Academic personal account. When on the society site, please use the credentials provided by that society.If you see ‘Sign in through society site’ in the sign in pane within a journal: Many societies offer single sign-on between the society website and Oxford Academic. Society member access to a journal is achieved in one of the following ways: If you cannot sign in, please contact your librarian. If your institution is not listed or you cannot sign in to your institution’s website, please contact your librarian or administrator.Įnter your library card number to sign in. Following successful sign in, you will be returned to Oxford Academic.When on the institution site, please use the credentials provided by your institution.Select your institution from the list provided, which will take you to your institution's website to sign in.Click Sign in through your institution.Shibboleth / Open Athens technology is used to provide single sign-on between your institution’s website and Oxford Academic. This authentication occurs automatically, and it is not possible to sign out of an IP authenticated account.Ĭhoose this option to get remote access when outside your institution. Typically, access is provided across an institutional network to a range of IP addresses. If you are a member of an institution with an active account, you may be able to access content in one of the following ways: Get help with access Institutional accessĪccess to content on Oxford Academic is often provided through institutional subscriptions and purchases. Example 4.1 Calculate the formula mass (FM) of NaOH using a table of atomic masses (AM). Therefore chemists often use the term formula mass to represent the total composition of such substances. For example, the molecular mass of ethanol, C2H5OH, is: (2×C)+(6×H)+(1×O) (2×12.0)+(6×1.0)+(1×16.0) = 46 When ionic compounds such as NaCl, Zn(NO3)2, andNH4Cl, are in the crystalline state or in solution form, they do not contain physically distinct uncharged molecular entities. The term applies only to compounds that exist as molecules, such as H2O, SO2, and glucose, C6H12O6. The molecular mass of a compound is the sum of the atomic masses of all the atoms in one molecule of the compound. of O) = (3×1.00)+(1×30.97)+(4×16.00) = 97.97 Once the actual formula of a chemical substance is known, the molecular mass can be determined in a manner similar to calculating the formula mass. For example, the formula mass of phosphoric acid, H3PO4, is 97.98 atomic mass units (amu), which is obtained by adding the atomic masses (taken from the periodic table) of the elements in one formula unit (i.e., 3 H + 1 P + 4 O). Formula masses are relative since they are derived from relative atomic masses. The formula mass is based on the ratio of different elements in a formula, as opposed to the molecular mass, which depends on the actual number of each kind of atom (compare section 6.2, “Empirical Formula”). ![]() The formula mass of a compound is the sum of the atomic masses of all the atoms in a formula unit of the compound, whether it is ionic or molecular (covalent). But there is a slight difference between the two terms, as explained below. Many chemists use the terms formula mass and molecular mass interchangeably when dealing with chemical compounds of known formula.
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