Transcription of Tutorial 2 FORMULAS, PERCENTAGE COMPOSITION, AND …
{{id}} {{{paragraph}}}
Example: confidence
Tutorial 2 FORMULAS, PERCENTAGE COMPOSITION, AND …
T-6 Tutorial 2 FORMULAS, PERCENTAGE COMPOSITION, AND THE MOLEFORMULAS: A chemical formula shows the elemental composition of a substance: thechemical symbols show what elements are present and the numerical subscripts show howmany atoms of each element there are in a formula unit. Examples:NaCl: one sodium atom, one chlorine atom in a formula unitCaCl2: one calcium atom, two chlorine atoms in a formula unitMg3N2: three magnesium atoms, two nitrogen atoms in a formula unitThe presence of a metal in a chemical formula indicates an ionic compound, which is composedof positive ions (cations) and negative ions (anions). A formula with only nonmetals indicates amolecular compound (unless it is an ammonium, NH4+, compound). Only ionic compounds areconsidered in this are tables of common ions in your lecture text, p 56 (cations) and p 57 (anions). Acombined table of these same ions can be found on the inside back cover of the lecture text. Asimilar list is on the next page; all formulas needed in this and subsequent Tutorial problems canbe written with ions from this formulas for ionic compounds is very straightforward: TOTAL POSITIVE CHARGESMUST BE THE SAME AS TOTAL NEGATIVE CHARGES.
care about percentage composition of pure chemical substances. Unless otherwise stated we always mean percent by mass (weight). The formula mass of a substance is the sum of the atomic masses of all the atoms in the formula. For example, the formula mass of sodium chloride, NaCl, 58.44, is the sum of the
Loading..
Tags:
Information
Domain:
Source:
Link to this page:
Please notify us if you found a problem with this document: