Chemistry Section 1

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• The soul of chemistry deals with the composition and properties of matter.
• The radioactive isotope of hydrogen is tritium.
• The electron was discovered by J.J Thomson.
• Sodium carbonate is produced by the Amonia solvay process.
• Graphite is a substance.
• Metallic substances are generally good conductors of electricity in both solid and liquid states.
• Plastic is not a crystalline substance.
• Covalent network crystals have a higher melting point than molecular crystals.
• A mixture of Potassium Nitrate, Powdered Charcoal, and Sulphur is called Gun Powder.
• The diameter of an atom is in the order of 0.2 nm.
• The soul of chemistry deals with the composition and properties of matter.
• The radioactive isotope of hydrogen is tritium.
• The electron was discovered by J.J Thomson.
• Sodium carbonate is produced by the Amonia solvay process.
• Graphite is a substance.
• Metallic substances are generally good conductors of electricity in both solid and liquid states.
• Plastic is not a crystalline substance.
• Covalent network crystals have a higher melting point than molecular crystals.
• A mixture of Potassium Nitrate, Powdered Charcoal, and Sulphur is called Gun Powder.
• The diameter of an atom is in the order of 0.2 nm.
• Mass spectrometer is used to determine relative abundance of isotopes.
• The number of peaks obtained in mass spectrometry shows the number of isotopes.
• The empirical formula of chloroform is CHCl3.
• Molecular mass of water (18g) means 1-gram molecule of water.
• Isotopes with even atomic number and even mass number are abundant.
• One mole of CO2 contains 22-gram electrons and 6.022 x 10^23 atoms of carbon.
• The number of isotopes of elements with even mass number and even atomic number is 154.
• The term “molecular formula” is not used for ionic compounds.
• The moles of each aluminium and oxygen react to produce 0.18 mole of product.
• Tin has the maximum number of isotopes.
• The volume occupied by 2.8 g of N2 at STP is 2.24 dm^3.
• The number of moles of CO2 containing 16 g of oxygen is 0.5.
• There are 86 isotopes with odd atomic number.
• The percentage of calcium in calcium carbonate is 40%.
• Mostly, elements have fractional atomic masses because atomic masses are average masses of isotopes proportional to their relative abundance.
• Sand is not a macromolecule.
• Isotopes of the same element have different number of neutrons.
• When cationic molecular ions pass through a strong magnetic field in a mass spectrometer, the lighter ions are fallen.
• The empirical formula can be applied to all mentioned compounds (NaCl, H2O, CCl4).
• The properties of an element mostly correspond to that isotope which has greater relative abundance.
• 1 atomic mass unit (a.m.u) equals 1.6 x 10^-27 kg.
• Isoelectronic species include F-, Ne, Na+.
• Molecular ions are formed by passing high-energy electron beam, ?, and X-rays.
• Isotopes possess the same chemical properties.
• Uni-negative ions are always formed in an exothermic process.
• The sample of isotopes of an element that needs not be vaporized in the vaporization chamber is gas.
• Avogadro’s number represents the number of particles.
• The size of a molecule depends upon atomicity and the shape of the molecule.
• Gold (Au) cannot be displaced by all other metals from its solution.
• Carbon (C) is not a mono isotopic element.
• The mass of decimole of electrons (NA) is 5.5 x 10^-4 micrograms.
• Isotopes possess properties that depend upon mass.
• Qualitative analysis is carried out for the identification of elements.
• Combustion analysis is performed to determine the empirical formula.
• Isotopes differ in properties that depend upon mass.
• The use of antifreeze in the automobile radiator is suitable because aluminum is resistant to corrosion by organic acids.
• The nucleus of an atom always contains protons.
• The reduction of the solution is occurring at the Ag electrode in an Al-Ag cell.
• Dempster’s mass spectrometer has five zones/parts.
• Solubility of CaF2 is 3.2 x 10^-11.
• Methyl alcohol is not used as a substitute for petrol.
• Oxygen (O2) diffuses faster than hydrogen (H2).
• As a substance moves from a solid to a liquid, molecules become more disordered.
• Benzene is a good solvent for fats, resins, and rubber.
• Two dissimilar substances have different composition.
• No statement regarding composition is correct.
• Fractional distillation is not used for the separation of a mixture.
• The molecular formula of the glucose is C6H2O6.
• Gasoline is a good solvent for most ionic compounds.
• A pure substance has a fixed composition.
• The density of petrol is higher than that of diesel.
• Chromatography is used to separate the components of a mixture.
• The process of crystallization is used for the separation of a pure solid from a solution.
• Solubility of CO2 is higher in water than in air.
• Distilled water is a compound.
• The density of ice is lower than that of water.
• Filtration can separate a soluble solid from a liquid.
• Gases have a definite volume.
• The composition of water is fixed.
• Ions have no effect on colligative properties.
• Sea water is not a mixture.
• The solubility of most gases in water decreases with increasing temperature.
• CO2 is a non-polar molecule.
• The mass of 1 molecule of oxygen is 32 amu.
• Evaporation is a cooling process.
• A pure substance always has a fixed composition.
• Sea water is a heterogeneous mixture.
• The solvent present in a solution is the solute.
• The process of sublimation is a cooling process.
• The density of milk is higher than that of water.
• The process of evaporation is used for the separation of components of a mixture.
• Rusting of iron can be prevented by keeping it dry.
• A solute is always a solid.
• Fractional distillation is used for the separation of components of a mixture.
• A mixture is a combination of two or more substances.
• Impure substances have variable composition.
• The separation of a mixture can be physical or chemical.
• Impure substances have a fixed composition.
• Substances change their composition when forming mixtures.
• Impure substances are also known as pure substances