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it varies for different types of semi conductors..

( C ) in the range of 10^-9 to 10^2 onm^-1cm^-1

Answer is d as the value range is between 10 to power -8 to 10 to power 2 per ohm per cm

Ans,D ,none of the above

Chirality is a geometric property of some molecules and ions. A chiral molecule/ion is non-superimposable on its mirror image. The presence of an asymmetric carbon center is one of several structural features that induce chirality in organic and inorganic molecules.

The term "chiral" (from the Greek for "hand") is applied to molecular systems whose asymmetry results in handedness; that is, the existence of a pair of nonsuperimposable mirror-image shapes (as illustrated by the relationship between one's right and left hands).

Lord Kelvin coined the term "chirality" in 1884, but it did not come into common usage until the 1960s. Many macroscopic examples of handed systems exist, including any object that features an inherent spiral or twist that can exhibit a left- and right-handed form: scissors, spiral staircases, screw threads, gloves, and shoes. Some mineralogical materials exhibit handedness in the solid state. In 1801 the crystallographer René observed that there were right- and left-handed quartz crystals, a phenomenon known as hemihedrism. The term "enantiomorphous" ("in opposite shape") was created to describe the macroscopic relationships between nonsuperimposable, mirror-image crystalline forms.

Chirality is a property of asymmetry important in several branches of science. The wordchiralityis derived from the Greek χειρ (kheir), "hand," a familiarchiralobject. An object or a system ischiralif it is distinguishable from its mirror image; that is, it cannot be superposed onto it.

The mole is the SI unit for the amount of a substance. Its symbol is mol. By definition: 1 mol of carbon-12 has a mass of 12 grams and contains 6.022140857 x 10^23 of carbon atoms

We know6.022 x 10^23 atoms are present in 1 mole

Then 3.011 x 10^23 atoms are present in 3.011 x 10^23 /6.022 x 10^23=.5 mole

The mass of substance containing the same number of fundamental units as there are atoms in exactly 12.000 g of12C. Fundamental units may be atoms, molecules, or formula units, depending on the substance concerned.

Chirality is a property of asymmetry important in several branches of science. The word chirality is derived from the Greek χειρ (kheir), "hand," a familiar chiral object. An object or a system is chiral if it is distinguishable from its mirror image; that is, it cannot be superposed onto it.

How do you determine chirality?

Look for carbons with four different groups attached to identify potentialchiralcenters. Draw your molecule with wedges and dashes and then draw a mirror image of the molecule.Ifthe molecule in the mirror image is the same molecule, it is achiral.Ifthey are different molecules, then it ischiral.May

when the carbon is bonded with four different group ,the carbon is said to be chiral and the process is called chirality

It is the basic unit in the International System of Units(SI), representing the amount of a substance expressed in grams containing as many atoms, molecules, or ions as the number of atoms in 12 grams of carbon-12 (which is Avogadro's number, or 6.022 × 1023).

Molecularity in chemistry is the number of molecules that come together to react in an elementary reaction and is equal to the sum of stoichiometric coefficients of reactants in this elementary reaction. Depending on how many molecules come together, a reaction can be unimolecular, bimolecular or trimolecular.

1. If a certain process has an enthalpy change∆H, the reverse of that process has an enthalpy change of -∆H.

2.Multiplying a thermochemical equation by a constant also multiplies the thermodynamic quantity by that constant.

3.The thermodynamic quantity for the reaction appliesas the equation is written. So, it can be used as a stoichiometric ratio with any of the reactants or products in the reaction.

1)For exothermic reaction, ΔH is negative whereas for endothermic reaction, ΔH is positive.

2)ΔH values are for the standard state of the substance ( 298 K and 1 bar pressure )

3) The coefficients of different substances represents the number of moles reacted and formed for the heat change represented in the equation.

4) The physical state of the different substances must be mentioned as the heat evolved or absorbed depends upon the physical state.

5) If the coefficient of the substances are multiplied or divided by some number , the value of ΔH is multiplied or divide by the same number.

6) If the reaction is reversed ,the sign of ΔH changes but the magnitude remains the same.

enthalpy of formation of OH- is the enthalpy of sum of -286.02+57.32 = -228.7 kJ

A positive (+)entropychange means anincreasein disorder. The universe tends towardincreased entropy. All spontaneous change occurs with anincreaseinentropyof the universe. The sum of theentropychange for the system and thesurroundingmust be positive(+) for a spontaneous process.

Definition of transitionmetal. : any of various metallicelements(such as chromium, iron, and nickel) that have valence electrons in two shells instead of only one. — called alsotransitionelement.Many scientists describe a "transition metal" as anyelementin the d-block of the periodic table, which includes groups 3 to 12 on the periodic table. In actual practice, the f-block lanthanide and actinideseriesare also consideredtransition metalsand are called "innertransition metals".

Transition series :The set / collection of transition metals is called transition series .

Definition - What does Transition Metals mean?

Transition metals are metals that possess unique and useful properties, mostly consisting of d-block transition elements in the periodic table.

There are about 56 transition elements that are subdivided into three main groups:

Main transition elements or d block elements (DBE)

Lanthanides elements

Actinides elements

Explains Transition Metals

Transition metals have incomplete inner electron shells that serve as transitional links between the most and the least electropositive in a series of elements. They are characterized by:

Multiple valences

Colored compounds

Ability to form stable complex ions

the flu is caused by virus it doesn't respond to antibiotics which spread to others easily

Because , sharing towels and vessels may cause flu to spread to us. through from the infected person. As the flu is caused by a virus that are communicable.

hardness of water is of two types one is permanent and other is temporary.temoprary hardness is due to calcium and magnesium bicarbonates. and permanent is due to salts of sulphates and chlorides

Manganeseexhibit the largest number of oxidation states. It shows the oxidation states +2, +3, +4, +5 ,+6, and + 7.The reason for that is the maximum number of unpaired electrons present in its outermost shell i.e. 3d54s2.

Silicosis

The chemistry of silicon differs markedly from that of carbon. Although carbon and silicon both have a normal valence of four and are similar in some ways, the differences between the chemical properties of their compounds are more striking than the similarities. There are groups of compounds where the differences are easily seen.

1. The oxides:The oxides of the two elements have very different properties. Carbon dioxide, CO2is a gas at room temperature and atmospheric pressure. Silicon dioxide, usually known as silica, has the empirical formula SiO2, but it is a solid with a very high melting point, not a gas. The reason for the difference is that silica consists of an extended network of silicon and oxygen atoms.

2. The hydrides:The hydrides of silicon have formulae such as SiH4, Si2H6etc, and are called silanes. These compounds are analogous to the alkanes CH4, C2H6etc. The reason that silanes are much more reactive than alkanes is not related to any “weakness” in the bonds.

Radius of the cone (r) = 40/2 cm = 20 cm = 0.2 mHeight of the cone (h) = 1 mLet l be the slant height of a cone.∴ l = √h2+ r2⇒ l = √12+ 0.22⇒ l = √1.04⇒ l = 1.02 mRate of painting =₹12 perm2

Curved surface of 1 cone = πrlm2 = (3.14 × 0.2 × 1.02)m2 = 0.64056m2Curved surface of such 50 cones = (50 × 0.64056)m2 = 32.028m2Cost of painting all these cones =₹(32.028 × 12) =₹384.34

Metal such as gold (Au) and platinum (Pt) present at the bottom of the activity series do not corrode easily.

The major reason behind silver turning black or tarnishes out is due to presence of various chemical reactions that occurs in contact with sulfur and Hydrogen. Our food items, everyday need products, polluted air consist of sulfur that leads to tarnish silver and make it to look black in color.

Silver will not react with sulphuric acid because it is least reactive metal to produce hydrogen by reacting with sulphuric acid.

Thanx

Q1A metal made by combining tow or more metallic elements,especially to give greather strength or resistance to corrosion

Thnks ji

a metal made by combining two or more metallic elements, especially to give greater strength or resistance tocorrosion.

Gold,silverandplatinumare all pure metals that don't containironand, therefore, don't rust.Stainless steeldoesn't rust because it is an alloy that contains the metalschromiumandnickel.Chromiummust comprise at least 10 percent of thesteelalloy forstainless steelto be rust resistant.

only gold silver copper & platinum metals occur in nature in large amount

Thnku ji

Thermosetting plastic can be bent or moulded easily on heating.

Looking at the chemical ‘formula’ we see that hydrogen peroxide is a molecule with one hydrogen atom and three oxygen atoms. That means that the atomic bond is weakened because H2O is much more stable and hold together than H3O.

Adding energy in the form of “light” which is really photons which carry energy breaks the bond with the extra oxygen atom and sets it free. So each H3O molecule reverts back to H2O plus one free oxygen atom.

Molecular weight of SO2=64.066g/mol(Since 32 + 16×2 = 64)

Molecular weight of SO2 =64.066g/mol

Along a period ( left to right) the different properties remains same in any period . you can understand well from below pic👇

mass of electron is 9.1 × 10 power -31 kg

Atomic number of carbon = 6

Hence first shell (K – shell) have 2 electrons and the remaining 4 electrons will be present the second shell, i.e. L- shell. Thus the distribution will be

K L

2 4

Atomic number of sodium =11. Hence, 1st shell (K-shell) will have 2 electrons and 2nd shell (L-shell) will have 8 electrons and 3rd shell (M-shell) will have 1 electron. Thus, the distribution will be

K L M

2 8 1

Decomposition Reaction represents the digestion in our body

rancidity is the answer

both addition of A and B will shift the equilibrium forwardoption 3

Mass of one Uranium atom = 238 amu. 1 amu = 1.67 x10-27 kg. ∴ 238 amu = 238 x 1.67 x10-27 kg= 397.46 x10-27 kg= 3.97 x10-25 kg. So, actual weight of uranium atom = 3.97 x10-25 kg.it is 3.97 *10^-22

molar mass of N2O is = (14+14+16) = 44gm

so, moles of N2O in 90kg is = 90*1000/44 ≈ 2045 moles

so moles of oxygen will be also 2045..and therefore mass of oxygen is 2045*(16g)/1000 = 32.72kg

The periodic table has impacted greatly on the human welfare in various ways, for example it has helped scientist discover what elements are needed for human survival.

The periodic table outlines clearly all the chemical elements that have been proven to be useful to mankind.

Oxygen for example as an element on the periodic table is used by mankind in various spheres of life including hospitals on patients who have breathing problems.Nitrogen element has impacted greatly in the chemical industry. It is used in the manufacture of fertilizers, dyes and explosives.Sodium element is useful in the human body. It helps body cells transmit nerve signals and regulate water levels in tissues and blood.Various elements on the periodic table have numerous impacts on human welfare.

Atomic Number: 24Symbol: CrAtomic Mass: 52

Manganese

Atomic Number: 25Symbol: MnAtomic Mass: 55

Iron

Atomic Number: 26Symbol: FeAtomic Mass: 56

Cobalt

Atomic Number: 27Symbol: CoAtomic Mass: 59

Nickel

Atomic Number: 28Symbol: NiAtomic Mass: 59

Copper

Atomic Number: 29Symbol: CuAtomic Mass: 64

Zinc

Atomic Number: 30Symbol: ZnAtomic Mass: 65

H HE LIBEBCNOFNENAMGALSIPCL AR KCA.

HydrogenHHeliumHeLithiumLiBerylliumBeBoronBCarbonCNitrogenNOxygenOFluorineFNeonNeSodiumNaMagnesiumMgAluminumAlSiliconSiPhosphorusPSulfurSChlorineClArgonArPotassiumKCalciumCaScandiumScTitaniumTiVanadiumVChromiumCrManganeseMnIronFeCobaltCoNickelNiCopperCuZincZn

HydrogenHHeliumHeLithiumLiBerylliumBeBoronBCarbonCNitrogenNOxygenOFluorineFNeonNeSodiumNaMagnesiumMgAluminumAlSiliconSiPhosphorusPSulfurSChlorineClArgonArPotassiumKCalciumCaScandiumScTitaniumTiVanadiumVChromiumCrManganeseMnIronFeCobaltCoNickelNiCopperCuZincZn

ABHydrogenHHeliumHeLithiumLiBerylliumBeBoronBCarbonCNitrogenNOxygenOFluorineFNeonNeSodiumNaMagnesiumMgAluminumAlSiliconSiPhosphorusPSulfurSChlorineClArgonArPotassiumKCalciumCaScandiumScTitaniumTiVanadiumVChromiumCrManganeseMnIronFeCobaltCoNickelNiCopperCuZincZn

HHELIBEBCNOFNENAMGALSLPCLARKCA.

(1,5) dimethyl heptane

2 ,5 di methyl heptane

2,5 dimethyl heptane( one more thing we start numbring we take small number prifix first)

2,5-dimethyl heptane

2,5 dimethyl heptane

2,5 dimethyl heptane

2,5-dimthyl heptane is the correct nomenclature of this compound.

2,5- dimethyl heptane

(1, 6)-methayl heptane

1) Propan-2-one2) 2-Hydroxypentanoic acid