Description : How compared with the melting points of ionic compounds the melting points of molecular solids tend to be?
Last Answer : Ionic compounds have a higher melting point.
Description : Ionic compounds have high melting and boiling points because A) less energy is required to break the strong interionic attraction B) large amount of energy is required to break the interionic attraction C) No energy is required D) None of the above
Last Answer : B) large amount of energy is required to break the interionic attraction
Description : Can ionic substances have high or low melting points?
Last Answer : Generally ionic substances have high melting and boiling points.
Description : Which of the following statements is not true about triacylglycerols? (a) When solids and semisolids at room temperature, they are called fats. (b) When liquids at room temperature, they are ... low melting points are composed of saturated fatty acids, causing them to be liquids at room temperature
Last Answer : Triacylglycerols with low melting points are composed of saturated fatty acids, causing them to be liquids at room temperature
Description : Which of the following is not a characteristic of organic compounds? (a) They usually have low melting points. (b) They usually are only slightly soluble or insoluble in water. (c) If water ... they seldom conduct an electric current. (d) Bonds which bind the atoms together are nearly always ionic.
Last Answer : Bonds which bind the atoms together are nearly always ionic.
Description : Choose the incorrect statement pertaining to organic compounds (1) They have low melting and boiling points (2) They do not dissolve in water (3) They are not easily combustible (4) They contain mainly carbon and hydrogen
Last Answer : They are not easily combustible
Description : Give reasons : (a) Diamond and rhombic Sulphur are covalent solids, but the latter has lower melting points. (b) Among NaCl and CsCl, CsCl is quite stable.
Last Answer : (a) Due to weak Vander Waal’s Force in Sulphur molecule. (b) CsCl coordination number is 8. It is surrounded by 8 anion tightly.
Description : Most covalent compounds (a) Behave like electrolytes in the molten state (b) Have high melting and boiling points (c) Are hard substances because of strong covalent bonds (d) Are more soluble in non-polar solvents than in polar solvents
Last Answer : Ans:(d)
Description : Why do alcohols have boiling points much higher than hydrocarbons of similar molecular weight? (a) Alcohols have greater van der Waals attraction forces. (b) Alcohol molecules have greater ... of volatilization. (d) Alcohols must overcome greater ionic forces in the process of volatilization.
Last Answer : Hydrogen bonds must be broken in the process of volatilization
Description : Hydrometer measures the specific gravity of liquids based on the principles of buoyancy. Pycnometer is used to measure the specific gravity of (A) Powder & granular solids (B) Liquids (C) Low melting point semi-solids (D) All 'a', 'b' & 'c
Last Answer : (D) All 'a', 'b' & 'c
Description : What are melting points and boiling points ? What is melting point and boiling point ?
Last Answer : Melting point refers to the process of melting a solid into a liquid at a certain temperature. Boiling point is the temperature at which a liquid evaporates. Therefore , the temperature at which a liquid begins to evaporate is called the 'boiling point' of that substance.
Description : The points noted by arrows are melting and boiling points of the metal zinc and magnasium. `Delta G^(0)` as a function of temperature for some reactio
Last Answer : The points noted by arrows are melting and boiling points of the metal zinc and magnasium. `Delta G^(0)` ... +Zn rarr Mg+ZnO` D. `ZnO+Mg rarrZn+MgO`
Last Answer : The points noted by arrows are melting and boiling points of the metal zinc and magnasium. `Delta G^(0)` as a ... gt 500^(@)C " but " lt 1000^(@)C`
Last Answer : The points noted by arrows are melting and boiling points of the metal zinc and magnasium. `Delta G^(0)` as a ... C. `500^(@)C` D. `1200^(@)C`
Description : Which statements about alkenes and alkanes of corresponding chain lengths is true? (I) Alkenes have slightly lower melting points than alkanes (II) Alkenes have slightly higher melting points than alkanes (III) Alkenes have higher boiling ... (a) I and III (b) II and IV (c) I and IV (d) II and III
Last Answer : I and III
Description : Melting point & boiling points of liquid oxygen are respectively - 218.8°C & - 183°C, while the same for liquid nitrogen is - 210°C & - 195.8°C respectively. The difference in melting points of liquid oxygen & liquid nitrogen is not equal to 8.8 (A) °C (B) °F (C) °K (D) °R
Last Answer : (B) °F
Description : Define intermolecular forces. Also write down effect of intermolecular forces on melting points & boiling points of substances?
Last Answer : The forces of attraction present between the molecules of a compound are called Intermolecular forces''. Effect of intermolecular forces on the m.p and b.p of substances If intermolecular forces of attractions in ... . And if these forces are weak then the m.p and b.p will be relatively lower.
Description : Metals have ______. (1) High melting and boiling point (2) Low melting and boiling point (3) High melting and low boiling point (4) Low melting and high boiling point
Last Answer : (1) High melting and boiling point
Description : The metals with very low melting points which melts by the temperature of palm are A) Sodium and potassium B) Lead and magnesium C) Aluminium and zinc D) Gallium and caesium
Last Answer : D) Gallium and caesium
Description : The noble gases have low boiling points because: w) their ionization potentials are very low x) only weak Van der Waals forces hold the atoms together y) they are produced by the fractional distillation of liquid air z) they have eight electrons in the outer shell
Last Answer : ANSWER: X -- ONLY WEAK VAN DER WAALS FORCES HOLD THE ATOMS TOGETHER
Description : Deemphasis in the receiver in effect attenuates modulating signal components and noise in what frequency range? A. dc B. low C. intermediate D. high
Last Answer : D. high
Description : Give reason .the melting point and boiling point of alkali metals are low
Last Answer : The melting and boiling points of the alkali metals are low indicating weak metallic bonding due to the presence of only a single valence electron in them.
Description : Some substances are good conductor of electricity in both the solid and liquid states. These substances are generally-------? A. ionic substances B. metallic substances (Answer) C. molecular solids D. covalent network solids
Last Answer : B. metallic substances (Answer)
Description : Why are ionic solids hard and brittle?
Last Answer : Ionic solids are brittle and hard as they are bonded with electrostatic bonds.
Description : Solids do not have which type of polarisation? a) Ionic b) Orientational c) Interfacial d) Electronic
Last Answer : c) Interfacial
Description : The following type of bonding is strongly directional in solids. (A) Vander Waal's (B) Ionic (C) Metallic (D) Covalent
Last Answer : D) Covalent
Description : Which class of solids could have London Forces the attractive forces between particles in crystal lattice positions? w) ionic x) covalent y) metallic z) molecular
Last Answer : ANSWER: Z -- MOLECULAR
Description : Forces in ionic crystalline solids are primarily which of the following? w)covalent x)electrostatic y)Van der Waals z)magnetic
Last Answer : ANSWER: X -- ELECTROSTATIC
Description : Ceramic nuclear metals compared to solid nuclear metals have (A) Higher melting points (B) Low strength at high temperature (C) More chances of radiation damage (D) Poorer corrosion resistance
Last Answer : (A) Higher melting points
Description : Pick out the wrong statement pertaining to the properties of glasses. Glasses generally have (A) High electrical insulation properties (B) Sharp melting points (C) Low co-efficient of thermal expansion (D) Compressive strength much greater than their tensile strengths
Last Answer : (B) Sharp melting points
Description : Change in volume of metals from absolute zero temperature to their melting points is (A) Almost same for all metals (B) Different for different metals (C) Less for low melting point metals (D) Less for high melting point metals
Last Answer : (A) Almost same for all metals
Description : Solids may be considered to be either crystalline noncrystalline. The basic difference between them is that a crystal, in contrast to a noncrystal: w) has a sharp melting point x) has an irregular array of atoms y) exhibits double refraction z) has a completely regular atomic or molecular structure
Last Answer : ANSWER: Z -- HAS A COMPLETELY REGULAR ATOMIC OR MOLECULAR STRUCTURE
Description : Water is a good solvent of ionic salts because - (1) It has no colour (2) It has a boiling point (3) It has a high dipole moment (4) It has a high specific heat
Last Answer : (3) It has a high dipole moment
Description : Increased serum levels of which of the following may be associated with a decreased risk of atherosclerosis? (a) Very low-density lipoproteins (VLDL) (b) Low-density lipoproteins (LDL) (c) Intermediate – density lipoproteins (IDL) (d) High-density lipoproteins (HDL) (e) Cholesterol
Last Answer : Ans: D
Description : Superconductors are those elements – (1) Whose conductivity is intermediate between metals and insulators (2) Whose resistance falls almost to zero at very low temperature (3) Which conduct electricity only at super-high temperature (4) Which conduct electricity only, at super-high temperatures
Last Answer : (2) Whose resistance falls almost to zero at very low temperature Explanation: Superconductivity is a phenomenon of exactly zero electrical resistance and expulsion of magnetic fields occurring in ... lines from the interior of the superconductor as it transitions into the superconducting state.
Description : Superconductors are those elements (1) Whose conductivity is intermediate between metals and insulators (2) Whose resistance falls almost to zero at very low temperatures (3) which turn into insulators at very low temperatures (4) which conduct electricity only at super-high temperatures
Last Answer : Whose resistance falls almost to zero at very low temperatures
Description : Distillation at reduced pressure is used for liquids which (a) Have high boiling points (b) Have low boiling points (c) Have high volatility (d) Decompose before their boiling points
Description : What type of solids are generally boiling?
Last Answer : Metals have a boiling point.
Description : Carbon compounds have usually low melting points and
Last Answer : boiling points.
Description : Why do covalent compounds have low melting points?
Last Answer : Because although the covalent bonds between the elements are strong, there are only weak forces between the molecules so they have low melting points
Description : Hot dipping process is used for coating a low melting point metal (e.g. Pb, Sn, Zn) on iron, steel & copper having relatively higher melting points. Which of the following is not a hot dipping process? (A) Galvanising (B) Tinning (C) Sherardizing (D) None of these
Last Answer : (C) Sherardizing
Description : Pick out the wrong statement. (A) Low intensity explosives are also called propellants, whereas high intensity explosive are called detonators (B) Gun powder comprises of 75% salt petre, 15% charcoal ... TNT is a hygroscopic explosive having very high melting point and is non-toxic to human being
Last Answer : (D) TNT is a hygroscopic explosive having very high melting point and is non-toxic to human being
Description : Flash distillation is suitable for separating the constituents of a binary system, which (A) Form minimum boiling azeotrope (B) Have very wide boiling points (C) Have very close boiling points (D) Form constant boiling azeotrope
Last Answer : (B) Have very wide boiling points
Description : Flash distillation is suitable for the separation of components (A) Having very close boiling points (B) Which form maximum boiling azeotrope (C) Having very wide boiling points (D) Which form minimum boiling azeotrope
Last Answer : (C) Having very wide boiling points
Description : Chylomicron, intermediate density lipoproteins (IDL), low density lipoproteins (LDL) and very low density lipoproteins (VLDL) all are serum lipoproteins. What is the correct ordering of these particles from the lowest to ... , IDL, LDL (C) VLDL, IDL, LDL, Chylomicron (D) Chylomicron, IDL, VLDL, LDL
Last Answer : Answer : B
Description : The noble gases have closed-shell electronic configuration and are monoatomic gases under normal conditions. The low boiling points of the lighter nob
Last Answer : The noble gases have closed-shell electronic configuration and are monoatomic gases under normal conditions. ... (C) unreactive D. (D) strongly basic
Last Answer : The noble gases have closed-shell electronic configuration and are monoatomic gases under normal ... flammablity D. (D) high calorific value
Last Answer : The noble gases have closed-shell electronic configuration and are monoatomic gases under normal ... reducing C. unreactive D. strongly basic