Molality

Let us learn about "molality"

An alternative unit of concentration to molarity is molality. The molality of a solute is the number of moles of that solute divided by the weight of the solvent in kilograms. For water solutions, 1 kg of water has a volume close to that of 1 liter, so molality and molarity are similar in dilute aqueous solutions.

The 'n' of a solute present per litre of the solution is called as Molarity, M of the solution .

Solved Problems on Molarity

1) Calculate the weight of Na₂CO₃ present in 100 ml of 0.1 M Na₂CO₃ solution ?

Solution : Volume of the solution = 100 ml = V ml

Weight of Na₂CO₃ dissolved = 'G' g (say)

Gram molecular weight of Na₂CO₃ = { (23*2) + 12 + (16*3) } = 106 g = GMW

Molarity of the given solution = 0.1 M = M

Substituting the values in the formula

M = G/GMW * 1000/V(ml)

0.1 = G/106* 1000/100

G = 0.1*106*100/1000 = 1.06 g

Weight of Na₂CO₃ = 1.06 g .

in our next blog we shall learn about exothermic reaction

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Theory test

Theory test is an assessment intended to measure the respondents' knowledge or other abilities. To learn science better practical test is better than theory test.

Most tests are designed to measure one of several characteristics: (1) learning ability, (2) learning achievement, (3) aptitude and interest, or (4) personality.

Another important function of test is that of a stimulator/motivator. The theory test is made up of two parts; the multiple choice part and the hazard perception part. You need to pass both parts to pass the theory test. Once you have passed the theory test you can then apply to take your practical driving test.

Theory is constructed of a set of sentences which consist entirely of true statements about the subject matter under consideration. However, the truth of any one of these statements is always relative to the whole theory. Therefore the same statement may be true with respect to one theory, and not true with respect to another.

In our next blog we shall learn about tundra animals

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just my two copper

I wish just my two copper coins become gold coins

Potassium iodide is an equipped by methods equivalent to those used to make potassium bromide. Potassium bromide forms the white crystals, m.p.680° C. It is very soluble in the water and gives the reactions of iodides. Here we will see about the chemical reaction of potassium iodide and the copper.

Copper is very important metal in industry as it has a great corrosion-resistance property. It has got good strength which is maintained at moderate temperatures. It is very ductile and can be worked into complex shapes. It can be very easily welded, soldered and riveted. It has got very high heat conductivity.

Copper is a great help when you are frustrated in a project. It will calm your mind and lead you into resolution of whatever has you stuck. It will also enhance your brain function

Copper is a very decorative metal, as well as being very useful. Use a Copper ring around your water glass, and sip while you work. You will stay energized and focused, and it's pretty!

Copper has long been used to ease the inflammation of arthritis and rheumatism. It will also help with a fever or other inflammatory reaction.

In our next blog we shall learn about gravity formula

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molecular formula

What is molecular formula?

Molecular formula is the chemical formula, which represents the actual numbers of atoms of each element present in a compound.

The mass of an atom of an element is called its atomic mass. The unit of atomic mass is any form of a mass like milligram, gram.Molar of a solution is defined as the quantity of gram-moles of solute softened in 1 liter of a solution. Molecular is as the grouping of atoms. A molecular is a combination of atom. Under the normal condition the elements are present in free state of an atom. The molecular mass of a matter is the calculation of the atomic masses of all atoms in a molecule of the substance.

A molecular shows all the physical and chemical properties of that matter. Molecules can obtain by same or different combination of elements.

Molecule formula is related to empirical formula.

Molecule formula = n * empirical formula

Where n= (molecular mass / empirical formula mass)

Example for molecules: C₂H₆:

The molecule benzene consists of two carbon atoms and six hydrogen atoms. Here the molecule benzene is the combination of carbon and hydrogen elements.

The molecular formula does not provide information on which atoms are arranged in a molecule. The structural formula is needed to determine the actual arrangement of the atoms in a molecule. Methyl alcohol, for example, consists of a carbon atom that has three hydrogen atoms and one oxygen atom bonded to it. The oxygen atom is, in turn, bonded to a fourth hydrogen atom. The molecular formula is CH₄O does not convey this specificity of arrangement as does the structural formula, CH₃OH.

Like the molecular formula, the structural formula of a substance gives the exact number of atoms of each element per molecule. In addition, however the structural formula depicts how the atoms are bonded to each other. As a result, the structural formula is essential for the determination of molecular shape and the properties associated with particular molecular geometric arrangements.

In our next blog we shall learn about "hydrogen chloride"

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causes of pollution

Let us know the main causes of pollution

Pollution is a human contribution to nature. Science has evolved technologies and technologies have helped the human welfare. In the process, the pollution has been a part of technology and therefore a part of human miseries

. Pollution is the addition to the ecosystem of something which has a detrimental effect on it. One of the most important causes of pollution is the high rate of energy usage by modern, growing populations.

Human activities mainly include:

• Industries for various human needs - directly and indirectly

• Agriculture for food production and industrial needs

• Health care for health of human beings and animals

• Transport for mobility of human beings

• Dwelling for settlement in city or villages

• Energy for various direct human needs and industrial needs

Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat, or light. Pollutants, the elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring, they are considered contaminants when they exceed natural levels. Pollution is often classed as point source or nonpoint source pollution. The act or process of polluting or the state of being polluted, especially the contamination of soil, water, or the atmosphere by the discharge of harmful substances.

In our next blog we shall learn about equilibrium constant

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Metallic bonding

Let us learn about "metallic bonding"

Metals tend to have high melting points and boiling points suggesting strong bonds between the atoms. Even a metal like sodium (melting point 97.8°C) melts at a considerably higher temperature than the element (neon) which precedes it in the Periodic Table.

Sodium has the electronic structure 1s²2s²2p⁶3s¹. When sodium atoms come together, the electron in the 3s atomic orbital of one sodium atom shares space with the corresponding electron on a neighbouring atom to form a molecular orbital - in much the same sort of way that a covalent bond is formed.

The force that binds together the atoms of metals is called metallic bond. The properties of metals cannot be explained in terms of common types of bonds such as ionic and covalent bonds. The inadequacy of these two type of bonds for metal formation can be explained as under.

The atoms of metals are all alike therefore they cannot form ionic bonds. Moreover, ionic compounds do not conduct electricity in the solid state and ionic compounds are brittle as opposed to properties of metals. The atom of metallic elements contain only 1 to 3 valence electrons, therefore these atoms cannot form covalent bonds, with noble gas configurations as they will remain incomplete. Covalent compounds are bad conductors of electricity and are generally liquids; properties opposed to metal formations. Thus, metals have a different model of bonding.

Thus Metallic bonding is the electromagnetic interaction between delocalized electrons, called conduction electrons and gathered in an "electron sea", and the metallic nuclei within metals.

In our next blog we shall learn about periodic table with charges

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Hydroelectric power plants

Let us learn about "Hydroelectric power plants"

Hydroelectric power plants capture the energy of falling water to generate electricity.

A turbine converts the kinetic energy of falling water into mechanical energy. Then a generator converts the mechanical energy from the turbine into electrical energy.
Hydro plants range in size from "micro-hydros" that power only a few homes to huge schemes like the Snowy River System that provide electricity for millions of people.

Advantages to hydroelectric power:

• Fuel is not burned so there is minimal pollution
• Water to run the power plant is provided free by nature
• Hydropower plays a major role in reducing greenhouse gas emissions
• Relatively low operations and maintenance costs
• The technology is reliable and proven over time
• It's renewable - rainfall renews the water in the reservoir, so the fuel is almost always there

There are three types of hydropower facilities: impoundment, diversion, and pumped storage. Some hydropower plants use dams and some do not.

In our next blog we shall learn about "chromosome structure"