Matter and Its Properties · SHS1 Chemistry

Lesson notes

Learning Objectives

Indicator: 1.1.1.LI.2 - Describe the atomic mass unit as an average mass.

By the end of the lesson, learners can:

Define the atomic mass unit (AMU) in relation to one-twelfth the mass of one atom of the carbon-12 isotope.
Explain why the AMU is described as an average mass rather than a fixed whole number.
Calculate the relative atomic mass of an element given the masses and abundances of its isotopes.
Use the periodic table to read and interpret relative atomic masses of elements.
Compare the actual mass of a particle to one-twelfth the mass of a carbon-12 atom.

Sign in with your phone number to read the full note and download the GES plan - free.

Sign in with phone number

Curriculum details

Strand: Physical Chemistry (Strand 1)
Sub-strand: Matter and Its Properties (1.1)
Content standard: 1.1.1.CS.2 - Demonstrate an understanding of the mole concept and its significance to the quantitative analysis of chemical reaction. 1.1.1.LO.1 Use the knowledge and understanding of the scientific practices in Chemistry to explain the structure of the atom as well as the stability of its nucleus. 1.1.1.LO.2 Use the mole concept to determine the amount and quantity of various substances involved in chemical reactions. 1.1.1.LO.3 Write mole ratios for chemical equations and apply it in quantitative analysis. 1.1.1.LO.4 Use the kinetic theory of matter to explain the behaviour of solids, liquids and gases under different conditions and describe the laboratory preparation of gases as well as their uses in everyday life.
Indicator: 1.1.1.LI.2 - Describe the atomic mass unit as an average mass.
Suggested placement: Semester 1, Week 12 (Week 12 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: NaCCA curriculum document, p. 34

Exemplars (from the NaCCA curriculum)

Talk -for -Learning: Through a presentation by your teacher, explain how the atomic mass unit, (AMU) of an individual particle (atom or molecule) is obtained by comparing the actual mass of the particle to one-twelfth the mass of 1 atom of the carbon-12 isotope.
Teaching and Learning Materials:
- * Worksheets with sample questions * Worksheets to record results. * Na CO 2 3 * CaCl 2 * Bolt and nuts * Resources for measuring volume and preparing solutions * Weighing scale
- * Calculator
- * Periodic table containing the elements with their relative atomic masses * Calculator * Beam balance or diagram of beam balance Substances of different weights
- * Apparatus (beaker, flask, weighing * Worksheet on the of substance and molar * Solid solutes
- Liquid solutes (e.g., water)
- CHARTS * Charts between other quantities
- for preparing solutions funnel, stirrer, volumetric scale), with sample questions interconversion of amount to number of entities quantities. (e.g., NaOH, NaCl) (e.g., HCl) Solvent
- showing interconversion amount of substance and
Assessment (1.1.1.AS.2). The document marks these depth-of-knowledge levels for this indicator: Level 1 Recall.