Topics in ChemistryChemistry Scheme of Work, SS1, First Term Chemistry Scheme of Work, SS1, Second Term Chemistry Scheme of Work, SS1, Third Term Compounds in Chemistry: Characteristics of Compounds Types of Mixture: Homogenous and Heterogeneous Mixtures Mixtures: Characteristics of Mixtures Physical Properties of Matter explained with Examples Chemical Properties of Matter explained with Examples Differences between Physical and Chemical Change Ionic Theory and Electrolysis Physical and Chemical Properties of Acids States of Matter: Characteristics of Solids Liquid State of Matter: Characteristics of Liquids Gaseous State of Matter: Characteristics of Gases Molar Mass, Worked Examples and Differences with Molecular Mass Elements: Characteristics of Elements Salts and Types of Salt in Chemistry Mixtures and Separation of Mixtures Mixtures and Separation of Mixtures - part 2 Mixtures and Separation of Mixtures - part 3
Academic Questions in Chemistry
The Separating Funnel is a technique used in the separation of mixtures. Another name for Separating Funnel is the _____ Funnel.
2NH4+(aq) + Ag+(aq) -> 2H4AgN
The equation above represents _____ acid.
A. Svante Arrhenius'
C. Gilbert Lewis'
E. Sir Isaac Newton's
F. Albert Einstein's
According to Brønsted Thomas Martin Lowry, an acid is defined as _____.
A. Any substance that produces hydrogen ion (H+) when dissolved in water
B. A substance that accepts electron pair in a chemical reaction
C. A substance that gives out hydronium ion (H3O+) when dissolved in water
D. A substance that donates a proton in a chemical reaction
E. A substance that reacts with a base to form salt and water
F. A substance whose hydrogen ions (H+) are displaced after a reaction with metals higher in the activity, reactivity or electrochemical series
Which of the following is NOT a characteristic of chemical change?
Which of the following statement is FALSE concerning a physical change _____.
The following substances will sublime EXCEPT _____.
Which of the following is a state of matter?
The ideal way of separating a mixture of blood is through _____.
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John Dalton, an English Chemist is considered the Father of modern Chemistry because of the understanding he brought into the composition of matter and the basis for their chemical reactions.
Recall that chemistry is the study of matter and the changes they undergo.
Some of the atomic theory which he postulated in 1808 had to be modified based on the discoveries of other scientists.
In this article, we will look into these atomic theories of Dalton and their modifications.
Based on the discovery made by Rutherford, atoms can no longer be regarded as indivisible because they can be further divided into the followings:
Protons: They are positively charged particles in the nucleus of an atom.
Neutrons: These particles have no charge (neutral) and are found in the nucleus of an atom.
Electrons: Negatively charged particles and revolve round the shell of atoms.
Quarks: A quark is a fast moving energy and is comprised of both the protons and neutrons in the nucleus of an atom.
The discovery of isotopes has shown that not all atoms of the same elements are similar in every aspect.
Isotopy is a phenomenon whereby atoms of the same element have the same atomic number but different mass number. As a result, the same element can have a different mass and density.
Note: The difference in the mass (mass number) of isotopes is a result of the varying number of neutrons in the nucleus of their atoms.
The mass number of an atom is defined as the sum of protons and neutrons in the nucleus of the atom.
Based on this above explanations, isotopes have the same number of protons (atomic number) and different number of neutrons.
Note: The Mass Spectrometry experiment conducted on (isotopic) atoms had given a confirmation to the existence of isotopes.
Some elements exhibiting isotopy include:
Also, the discoveries of isobars have shown that the atoms of different elements are not completely different.
Isobar is a phenomenon whereby atoms have different atomic numbers but the same mass number. For instance:
With regards to ordinary chemical reaction, this statement remains valid.
After the discovery of radioactivity, the various radioactive elements have shown that atoms can be created (through a process called nuclear fusion) and destroyed (through a process called nuclear fission).
Example of radioactive elements are Thorium-232 and Uranium-238
This statement is true for simple inorganic chemical reaction. With regards to complex organic compounds or molecules, the statement becomes false because they don’t combine in simple whole numbers; rather, they do so in complex numbers. For instance, glucose molecule has a chemical formula of C12H22O11.
Starch is another organic compound that contains many repeating units of simple sugars and with a chemical formula of (C6H10O5)n, where "n" is a large whole number.
This theory cannot explain allotropy.
Allotropy is phenomenon whereby atoms of the same element exist in different forms but in the same physical state.
For instance; carbon in its solid state can exist in four different forms. These are:
Note: The above forms of carbon have got different physical properties or characteristics. For instance, graphite is soft while diamond is very tough (hard).
1. His theory gave a clearer explanation to the laws of chemical combination which includes:
2. Dalton created the distinctions between atoms, molecules and compounds.
You can read on Physical and Chemical Changes here
3. His work paved way for the discovery of atomic bomb.
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Amazing facts in Chemistry
The only letters that failed to appear on the periodic table are letters:
Gold and copper are the only two non-silvery colored metals.
Copper is the only metal that is naturally antibacterial. This is why you would see some children utilize 'copper' water bottles in schools
Water actually freezes faster when it’s warm than when it’s cold
Most element in their pure state exists physically in different forms. For instance, pure carbon can exist as both diamond and graphite. This phenomenon is called allotropy.
If you pour a handful of salt into a full glass of water, the water level will go down rather than overflowing the glass.
Similarly, if you mix half liter of water and half litre of alcohol, the total volume of the liquid will be les than one litre
NOTABLE POINTS IN Chemistry