Topics in ChemistryLe Chatelier's Principle: Changes in Concentration and Pressure explained in Dynamic Equilibrium Chemical Equilibrium: Dynamic Equilibrium in Chemistry Static and Dynamic Equilibrium explained with their Differences Chemistry 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
Academic Questions in Chemistry
Which of the following statement is false concerning hydrocarbons?
A. Hydrocarbons can be aromatic
B. Hydrocarbons are made up of carbon and hydrogen only
C. Alkynes are aliphatic hydrocarbons
D. Alkenes have a carbon-carbon double bond in their structure
E. Benzene ring has a carbon-carbon triple bond in its structure
F. Hydrocarbons are the main constituents of petroleum and natural gas
The ability of carbon to form long chain of itself is called _____.
A. Carbon chain reaction
E. Organic chemistry
F. Carbon moleculation
Calculate the relative molecular mass of methane. (Carbon = 12.001, H = 1.00794).
A. 13.00894 amu
B. 11.00206 amu
C. 12.00794 amu
D. 14.001 amu
E. 15.001 amu
F. 16.033 amu
Which of he following is not a fact concerning gold?
A. 24 karat gold is the purest gold element
B. It is the 50th rarest metal amongst all elements found beneath the earth crust
C. It is the most malleable and ductile pure metal ever known
D. It is the only metal with a golden color
E. Gold is non toxic and can be eaten with food
F. It's present inside the earth crust in all seven continents
Which of the following is not an example of a chemical change?
Which of the following is not a fraction of crude oil?
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
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Before we look into the physical properties of metals, it will be great if we first understood what metals really are.
Majority of the naturally occurring elements on earth are metals. They normally do not exist in their pure form because rocks, sand and other earthen particles are mixed with them.
Metals are called ore in their impure state; for instance iron ore, tin ore and zinc ore.
When extracted from the earth, they need to be purified before being used for the various beautiful things around us like airplanes, cars, engine and so on. A method of Metal purification is via a process termed electrolysis
Note: Metals are generally solids at room temperature.
Metals will normally lose electrons(s) to form positive ions (called cations) in a chemical reaction. They are thus electropositive elements.
Ideally, one of the ways to identify an object is through its physical properties or characteristics; and metals are no exception.
Note: Metals have also got chemical properties too.
Below are the physical properties or characteristics of metals:
They exist in the solid state at room temperature.
The metal Mercury is an exception because it exist in the liquid state at room temperature.
They generally have high densities. Of all metals, Lithium has the lowest density while Osmium has the highest density.
With regards to heat and electricity, a metal is an object that can transfer heat and electricity. Metals are generally good conductors of heat and electricity.
Note: Metal conducts heat through a process termed conduction.
Lead is the poorest conductor of heat while Bismuth is the poorest conductor of electricity.
The metal Silver is the greatest conductor of both heat and electricity.
This is a feature that has to do with the state or quality of being able to be polished and the ability to shine, glow, sparkle, glitter or reflect light. Metals generally have the luster quality.
Malleability is the ability of an object to withstand the process of hammering; such that it can be bent or flattened and eventually made into thin sheets called foils.
Metals are able to take different shapes because of their malleability feature. Gold is the most malleable metal.
Being ductile is the ability of an object to be drawn into wires. For instance, copper wires and aluminium wires are wires drawn from copper and aluminium respectively.
Metals are generally ductile; and Platinum is the most ductile of all.
Most Metals are generally poor magnets.
Note: A metal like Iron is well magnetised.
The melting point (also called liquefaction point) of a substance is that point at which it changes from solid to liquid.
Metals generally have high melting points.
The metal Tungsten (W) has got the highest melting point at 3422°C while Mercury (Hg) has the lowest melting point at -38.829°F.
The boiling point of a liquid is the temperature at which the vapour pressure of the liquid equals the external atmospheric pressure.
When metals are heated, they melt into liquid before they start to boil. Metals generally have high boiling points.
Since mercury exists as liquid, it has the lowest boiling point of all metals.
The metal Tungsten has got the highest boiling point at 3422°C.
With the exception of Lithium (Li), Sodium (Na) and Potassium (K) which are soft metals, most metals are grenerally hard.
Most metals come in a variety of colors while some are opaque. Below are some colors of metals:
Note: Most metals are coloured silver.
This is the ability of an object to make sound. Metals are generally sonorous.
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Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.
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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
A major challenge encountered when calculating molecular mass is that it becomes difficult or impossible to calculate especially when the relative molecular mass of large molecules, polymers and macromolecules are involved.
Examples of large molecules (with indefinite molecular masses) include carbohydrates, cellulose and complex sugars.
The large molecules (above) have no specific chemical formula throughout their volume.
Understand that Relative Molecular Mass prove to be useful only when we calculate substances with small and definite molecular sizes. This was proven through the Modifications of Dalton's Atomic Theory.
Calculate the Relative Molecular Mass of Methane (CH4). (Carbon=12.001 and H=1.00794)
Molecular Mass of Methane = 16.033 amu
Calculate the Relative Molecular Mass of Water (H2O). (Oxygen=15.9994 and Hydrogen=1.00794)
Molecular Mass of Water = 18.015 Da
Below are some facts about gold
It is the only metal that has a gold (golden) color.
Gold is present inside the earth crust in all the seven continents.
Pure gold is soft and very stretchable (It can even be stretched into threads).
The Latin name of Gold is aurum which means 'shining dawn'. For this reason, its chemical symbol is 'Au'.
Gold is a very good conductor of electricity. This is why it’s sometimes used in making USB and audio cables.
Gold is non toxic and can be eaten with food. It is sometimes added to desserts in some expensive restaurants.
The term Gold originated from an ancient English word 'geolu' which means yellow.
24karat gold is the purest gold element.
An acid is a substance that produces Hydrogen ions (H+) when dissolved in water (or when in the form of an aqueous solution).
Svante Arrhenius definition of Acid
An acid is a substance that donates a proton in a chemical reaction.
Brønsted Thomas Martin Lowry definition of Acid
An acid is a substance that accept an electron pair in a chemical reaction.
Gilbert Newton Lewis definition of Acid
Finally, Acids can also be also defined as substances that gives out hydronium ion (H3O+) when dissolved in water.
In summary, all acids will always contain the positive H+ (cation) and an anionic group in their formula. For instance, the acid HCl (Hydrogen Chloride) contains H+ as cation and Cl- as its anion.