Unit 1 Overview: Moles and Atomic Structure (Video Notes)

Flashcards covering key concepts from the lecture notes on moles, molar mass, Avogadro's number, atomic structure, periodic table, and related practice problems.

What unit is used to compare observations of macroscopic chemical systems?

The mole.

What information about an element can be predicted from its periodicity and atomic number?

Properties and trends based on its position in the periodic table (periodic trends and identity).

What does electron configuration describe?

The arrangement of electrons in an atom; the electron structure.

What is the equation relating amount of substance n, mass m, and molar mass M?

n = m / M.

Why can't you count particles directly in the lab?

Because particles are too numerous; we use mass or moles to relate to particle numbers.

What is Avogadro's number?

6.022 × 10^23 mol^-1; the number of particles per mole.

What is the relationship between amu and Da?

1 amu ≈ 1 Da (Dalton).

Which isotope is used as the standard for atomic masses?

Carbon-12 (C-12).

How many grams does one mole of carbon-12 weigh?

12 grams.

How many amu are in one gram?

Approximately 6.022 × 10^23 amu.

What is the approximate mass in amu of a proton?

About 1 amu.

What is the approximate mass in amu of a neutron?

About 1 amu.

What is the approximate mass of an electron in amu?

Negligible, about 1/1823 amu.

What is a period on the periodic table?

A row; e.g., period 3.

What is a group on the periodic table?

A column; e.g., group 2; some groups have names.

Name the groups: alkali metals, alkaline earth metals, transition metals, halogens, noble gases.

Group 1: alkali metals; Group 2: alkaline earth metals; Groups 3-12: transition metals; Group 17: halogens; Group 18: noble gases.

What does the atomic number represent?

The number of protons; defines the element.

What is the difference between atomic mass and molar mass?

Atomic mass is the average mass of a single atom in amu; molar mass is the average mass of a mole of atoms in g/mol.

What is the unit of molar mass?

g/mol.

How many particles are in one mole?

6.022 × 10^23 particles.

What is the molar volume of an ideal gas at STP?

22.4 L per mole.

What is the formula for molarity (M)?

M = moles of solute / liters of solution.

How many atoms are in 10.0 g of O2?

3.76 × 10^23 atoms.

If 2.00 × 10^12 gold atoms are synthesized and priced at $61.67 per gram, what is the total value?

About $4.03 × 10^-8.

Rank the following by decreasing number of moles for 15.0 g samples of NO2, CO2, and SO2.

CO2 > NO2 > SO2.

What does PES stand for in chemical representations?

Potential Energy Surface.