Some important units of measurement

1-1. SI units (Le Système International d'Unités):

• International System of Units ( 국제단위계 )

• 1960 년 제 11 차 국제도량형총회 (CGPM, Conférence Générale

des Poids et Mesures) 에서 명칭과 약칭 "SI" 를 채택 결정

• 7 개의 기본 물리량 , 이름 , 기호 선정

Chapter 1 Measurements

Using prefixes as multipliers

Rather than using exponential notation, we often use prefixes from Table 1-3 to express large or small quantities.

Converting between unitsAlthough SI is the internationally accepted system of measurement in science, other units are encountered. Useful conversion factors are found in table 1-4.

1. The mole▶ 약자는 mol 임▶ 화학종이 아보가드로수 (6.022 Х 1023 개 ) 만큼 있으면 1mol ▶ 몰질량 (molar mass, M) 은 화학종 1mol 의 질량 ( 단위 , g) nx: X 의 몰수 (mol),

Mx: X 의 몰질량 (g/mol) massx: X 의 질량 (g)

▶ X 의 몰수 (moles) ▶ X 의 밀리몰수 (mmoles)

1-2. chemical concentrations

Ex) 분자의 몰질량 (M) 계산 : 원자질량을 모두 합한 다음 g 을 붙임 . Formaldehyde(CH2O) 및 glucose(C6H12O6) 의 몰질량 ?

Solutions and their concentrations

Molar concentration (c, molarity): 단위 (M, mol/L)

■ Analytical molarity ( 분석몰농도 , mol/L)

■ Equilibrium molarity ( 평형몰농도 , mol/L)

(at equilibrium)

▶ [ ] 기호를 사용하여 표시하기도 함

Percent concentration (%) Solution = solute + solvent

Parts per million (ppm) and parts per billion (ppb)

Parts per million parts billionSometimes, composition is expressed as parts per million (ppm) or

parts per billion (ppb), which mean grams of substance per million or billion grams of total

solution or mixture.

1-3 preparing solutionsTo prepare a solution with a desired molarity from a pure solid or

liquid, we weigh out the correct mass of reagent and dissolve it in a volumetric

flask ( figure 1-3)

Solution-diluent volume ratios

( 용액 - 묽힘 부피비 )진한용액의 부피 : 묽히는 용액의 부피 = A : B

⇒ 1 : 4 HCl 용액 = 진한 HCl 부피 1 + 4 부피의 물

p-function

Stoichiometric calculations

⇒ 양론계수가 맞추어진 화학방정식은 반응물과 생성물의

몰비에 대한 정보를 제공

2 mol 1 mol 2 mol 1 mol

1-4 Stoichiometry calculations for Gravimetric Analysis

Chemical analysis based on weighing a final product is called gravimetric analysis.

1-5. introduction to titrations

Procedures in which we measure the volume of reagent needed to react with analyte (the sub-stance being measured) are called volumetric analysis.