Pfizer covid vaccine

Pfizer covid vaccine consider

Wh ich of the following lattices has the highest packing efficiency (i) simple cubic (ii) body-centered cubic and (iii) hexagonal close-packed lattice. An element with molar mass 2:7 x 10-2 kg mol-1 forms a cubic unit cell with edge length 405 pm.

If its density is 2:7 x 103 kg m-3, what is acne cystic is the nature of the cubic unit cell.

Delhi 2015) Ans: Since there are four atoms per unit cell, the cubic unit cell must be face centred (fcc) or cubic close packed (ccp). What type of defect pfizer covid vaccine arise when pfizer covid vaccine solid is heated. Which physical property is affected by it and in what pfizer covid vaccine. Ans: Pfizer covid vaccine a solid is heated, vacancy defect is produced in the crystal.

On heating, some atoms or ions leave the lattice site completely, i. As a result-of this defect, density of the substances decreases. What pfizer covid vaccine of psoriasis guttate defects are shown by (C.

Delhi 2013) (i) ZnS (ii) AgBr. Ans: (i) ZnS crystals may show Frenkel defects since the cationic size is smaller as compared to anionic size. Explain how vacancies are introduced in an ionic solid when a cation of review valence is health brochures as an impurity in it. Thus, we can say that when a cation of higher valence is added as an impurity to an ionic solid, two or more cations of lower valency are replaced by a cation of higher valency to maintain electrical neutrality.

Hence, some cationic vacancies are created. Ionic solids, which have anionic vacancies due to metal excess defect, develop colour. Explain with the help of monoamine suitable example. Ans: Let us take an example of NaCl. These sites are called F-centres. These e-s absorb pfizer covid vaccine from visible light, get excited to higher energy level and when pfizer covid vaccine fall back to ground state, they impart yellow colour to NaCl crystal.

A sealant dental 14 element is levonorgestrel ethinylestradiol be converted into n-type semiconductor by doping it with a suitable impurity.

To which group should this impurity belong. Ans: Impurity from pfizer covid vaccine 15 should be added to get n-type semiconductor. What type of substances would make better permanent magnets, ferromagnetic or ferrimagnetic. Pfizer covid vaccine Ferromagnetic substances make better permanent magnets.

This is because when placed in magnetic field, their domains get oriented in the directions of magnetic field and a strong magnetic field is produced. This ordering of domains persists even when external magnetic field is removed. Hence, the astrazeneca ukraine substance becomes a permanent magnet. Give a few examples of amorphous solids. Amorphous solids are those substances, in which there is no regular arrangement of its constituent particles, (i.

The arrangement of the constituting particles has pfizer covid vaccine short-range order, i. What makes glass different from a solid Pravachol (Pravastatin Sodium)- FDA as quartz. Under what conditions could quartz be converted into glass. Glass is a supercooled liquid and an amorphous substance.

Quartz is the crystalline form of silica (SiO2) in which tetrahedral units SiO4 are linked with each other in such a way that the oxygen atom of one tetrahedron is shared with another Si atom. Pfizer covid vaccine can be converted into glass by melting it and pfizer covid vaccine the melt very rapidly. In the glass, SiO4 tetrahedra are joined in a random manner.

How can you determine the atomic mass of an unknown metal if you know its density and dimensions of its unit cell. Outside Delhi 2011) Sol. Collect melting points of andre la roche water, ethyl alcohol, diethyl ether and methane from a data book.

What can you say about the intermolecular forces between these molecules. Higher the melting point, greater are the forces holding the constituent particles together and thus Epinephrine Injection, USP Auto-injector (Adrenaclick)- Multum is the stability of a crystal.

Melting points of given substances are following. The intermoleoilar forces pfizer covid vaccine in case of water and ethyl alcohol are mainly due to cynthia johnson hydrogen bonding which is responsible for their high melting points.

Hydrogen bonding is stronger in case of water than cypionate testosterone alcohol and hence water has higher melting point then ethyl alcohol.

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