Chapter 4 - Chapter 4 Calculation Used in Analytical...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 4 Calculation Used in Analytical Chemistry • Some Important Units of Measurement SI units: Scientists throughout the world have adopted a standardized system of units known as the International System of Units or SI units . The system is based on metric system (such as Mass: kg; Length: m; Time: s; Temperature: K; Amount of substance: mol; Electric current: A etc.). Other units are derived from the base units. Prefixes are used with the base units and other derived units to express small or large measured quantities in terms of a few simple digits (such as giga: 10 9 ; mega: 10 6 ; Kilo: 10 3 ; deci: 10-1 ; centi: 10-2 : milli: 10-3 ; micro: 10-6 ; nano: 10-9 ; pico: 10-12 ; femto: 10-15 ; atto: 10-18 etc.). The Mole: The mole is the SI unit for the amount of chemical species. The mole is associated with a chemical formula and Avogadro’s number (6.022 x 10 23 ) of particles. The molar mass (M) of a substance is the mass in grams of one mole of the substance. Molar masses are calculated by summing the atomic masses of all the elements appearing in a chemical formula. Molar Mass of formaldehyde CH 2 O Molar Mass of glucose C 6 H 12 O 6 M mo lC mo lCH O g mo lC mo lH mo lCH O g mo lH mo lO mo lCH O g mo lO g mol CH O CH O 2 1 12 0 2 10 1 160 300 2 2 2 2 = × + × + × = . . . . / M mo lC mo lC H O g mo lC mo lH mo lC H O g mo lH mo lO mo lC H O g mo lO g mol C H O C H O 6 12 6 6 12 0 12 10 6 160 180 6 12 6 6 12 6 6 12 6 6 12 6 = × + × + × = . . . . / Mass and Weight: Mass is an invariant measure of the amount of matter in an object. Weight is the force of attraction between an object and earth. The weight of an object depends on the location because gravitational attraction varies with geographic location. The mass of an object remains constant regardless of locations. A chemical analysis is always based on mass so that the results will not...
View Full Document

This note was uploaded on 05/09/2010 for the course CHEM 3245 taught by Professor Anwara.bhuiyan during the Spring '10 term at Arkansas Tech.

Page1 / 21

Chapter 4 - Chapter 4 Calculation Used in Analytical...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online