Chemical Formulas, Equations, and Reaction Yields

University:
Boston University
Course:
CAS CH 102 | General Chemistry 2
Academic year:

2023
Views:

127

Pages:

3
Author:

Cora Boone

TP Which contains the most molecules? 1. 2. 3. 4. 1 g of H 45 g of Cl 28 g of N 24 g of CH TP The molar mass of Cl is 35.453 g. 37Cl has a natural abundance of 24.24%. Which of the following statements is true? 1. The mass of one atom of naturally occurring Cl is 35.453 g divided by Avogadro's number 2. The mass of one atom of naturally occurring Cl cannot be 35.453 g divided by Avogadro's number. 3. Neither of the statements is true. • Compete: Atomic weight • Chemist’s dozen: The mole • Example problems: Chemical formulas, equations, and reaction yields Terms to distinguish Relative atomic mass, 𝐴r: ratio of mass of an isotope relative to mass of 1/12 of one 12C atom 𝐴r of 13C is 13.00335 unitless Atomic mass unit, u: 1/12 mass of one 12C atom 1u 1/12 12 g / 𝑁A g / 𝑁A 1.66054 10‒24 g Atomic weight: average of relative atomic masses of an element Atomic weight of C is 12.01 unitless Molar mass, 𝑀: Mass in grams numerically equal to atomic weight; that is, the mass in grams of 𝑁A “average atoms” of an element Molar mass of C is 12.01 g Mole: Count by weighing Chemist’s dozen: mole  counting by weighing TP Which contains the most molecules? 1. 2. 3. 4. 1 g of H 45 g of Cl 28 g of N 24 g of CH The mass in g of 1 mol of any element is called its molar mass Number of particles in 1 mol is 𝑁A 6.02214076 x 1023 Each of these amounts contains the same number of atoms Mass to molecules Which contains the most molecules? 1 g of H : 1 g 0.5 mol 45 g of Cl : 45 g 0.64 mol 28 g of N : 28 g 1.0 mol 24 g of CH : 24 g 1.5 mol TP Which of the following contains the smallest number of atoms? 1. 2. 3. 4. 187 g of liquid mercury, Hg 1400 u of uranium, U 6 1024 atoms of sodium, Na 2 mol of hydrogen gas, H2 Problem: 7e 2.7; 8e 1.31 TP Which of the following contains the largest number of atoms? 1. 2. 3. 4. 187 g of liquid mercury, Hg 1400 u of uranium, U 6 1024 atoms of sodium, Na 2 mol of hydrogen gas, H2