OVERVIEW OF TOPICS COVERED IN THIS BLOG

If you have just stumbled on this page by chance, YOU ARE WELCOME! The are many topics covers in this blog. You can do a search on the blog using various phrases or subject matter. Here is a summary of some of the topics covered.

Lesson 1:	Basic structure of atom Cell structure and function Functions of cell organelles Types of tissues
Lesson 2:	Movement of substances across the cell membrane Acids and bases, pH scale Carbohydrates, proteins, lipids and nucleic acids
Lesson 3:	Basic structure of the eye Basic structure of the ear Nervous system
Lesson 4:	Circulatory system Introduction to mechanics (motion/forces) Electrical circuits
Lesson 5:	Balancing chemical equations and writing formulas Essentials of photosynthesis and respiration Classifying organic compounds Magnetism Electromagnetism
Lesson 6:	Interpretation of graphs and pictograms Analyzing and making conclusions from experiments Data analysis
Lesson 7:	Endocrine system Digestive system Genitourinary system
Lesson 8:	Reproduction in mammals Basic parts of a flower Reproduction in plants (the process of pollination Genetics
Lesson 9:	Modes of heat transfer Calculating heat energies and phase diagrams Temperature conversions (Kelvin, Celsius, Fahrenheit)
Lesson 10:	Gas laws (Boyle, Charles, Gay-Lussac) Types of energy (Potential, kinetic, etc…..) Chemical bonds, equilibrium and equilibrium constants Mixtures, types of solutions, solubility
Lesson 11:	Concepts of the food pyramid, food web and food chain Light (diffraction, refraction, reflection, dispersion) Basic concepts on waves Sound waves Catalyst and enzymes
Lesson 12:	Symbiosis Ecology The Electroscope Radioactivity and half-life Tropism Tropism

RELATIVE ATOMIC MASS QUESTIONS

Question 1:
Calculate the relative atomic mass of silver if it occurs naturally as 51.84% silver-107 and 48.18% silver-109.

Solution:
Relative atomic mass = 0.5184 (107) + 0.4816 (109)
Relative atomic mass = 107.96

Question 2:
Calculate the relative abundance of each isotope of copper if it consists of two isotopes, copper-63 and copper-65. Its relative atomic mass is 63.62.

Solution:
Let Abundance of copper-63 = x
Then, Abundance of copper-65 = 1-x

Relative atomic mass = 63x + 65(1-x)
                                      63x + 65(1-x) = 63.62
                                       x = 0.69
That is, 69% of copper-63 and 31% of copper-65

THE MASS SPECTROMETER

The mass spectrometer is an instrument used for analyzing samples of elements and compounds. It consists of six basic stages: Injection, Vaporization,  Ionization, Acceleration, Deflection, and  Detection.

Click to view a diagram of the mass spectrometer.

• The sample is injected into the instrument.
•  It may be vaporized by heating. 
• The vaporized sample is then passed into an ionizing beam of electrons which knock electrons off the sample to create positive ions.
• These positive ions are then accelerated by some electrostatically charged plates into a magnetic field.
• The magnetic field then deflects the particles according to their mass/charge ratio.
• The deflected ions then arrive at the detector.

You can test yourself on the atomiser by clicking this link. It is a timed quiz.