Chapter 4

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

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

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.

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

View Full Document
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.

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

View Full Document
Molar Mass of formaldehyde CH 2 O Molar Mass of glucose C 6 H 12 O 6 M m o l C m o l C H O g m o l C m o l H m o l C H O g m o l H m o l O m o l C H O g m o l O g m o l C H O C H O 2 1 1 2 0 2 1 0 1 1 6 0 3 0 0 2 2 2 2 = × + × + × = . . . . / M m o l C m o l C H O g m o l C m o l H m o l C H O g m o l H m o l O m o l C H O g m o l O g m o l C H O C H O 6 1 2 6 6 1 2 0 1 2 1 0 6 1 6 0 1 8 0 0 6 1 2 6 6 1 2 6 6 1 2 6 6 1 2 6 = × + × + × = . . . . /

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

View Full Document
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
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern