Скачать с ютуб Exercise class 9 science chapter 4 measurement of matter । Exercise measurement of matter । Std 9 в хорошем качестве

Exercise class 9 science chapter 4 measurement of matter । Exercise measurement of matter । Std 9

Exercise class 9 science chapter 4 measurement of matter, Exercise measurement of matter, Std 9 science chapter 4, Class 9 science, std 9 general science, Std 9 general science, Question answer measurement of matter, Workshop measurement of matter, Give examples. a. Positive radicals b. Basic radicals c. Composite radicals d. Metals with variable valency e. Bivalent acidic radicals f. Trivalent basic radicals 2. Write symbols of the following elements and the radicals obtained from them, and indicate the charge on the radicals. Mercury, potassium, nitrogen, copper, sulphur, carbon, chlorine, oxygen 3. Write the steps in deducing the chemical formulae of the following compounds. Sodium sulphate, potassium nitrate, ferric phosphate, calcium oxide, aluminium hydroxide 4. Write answers to the following questions and explain your answers. a. Explain the monovalency of the element sodium. b. M is a bivalent metal. Write down the steps to find the chemical formulae of its compounds formed with the radicals : sulphate and phosphate c. Explain the need for a reference atom for atomic mass. Give some information about two reference atoms. d. What is meant by Unified Atomic Mass? e. Explain with examples what is meant by a 'mole' of a substance. 5. Write the names of the following compounds and deduce their molecular masses. Na 2 SO 4 , K2 CO 3 , CO2 , MgCl2 , NaOH, AlPO 4 , NaHCO3 6. Two samples ‘m’ and ‘n’ of slaked lime were obtained from two different reactions. The details about their composition are as follows: ‘sample m’ mass : 7g Mass of constituent oxygen : 2g Mass of constituent calcium : 5g ‘sample n’ mass : 1.4g Mass of constituent oxygen : 0.4g Mass of constituent calcium : 1.0g Which law of chemical combination does this prove? Explain. 7. Deduce the number of molecules of the following compounds in the given quantities. 32g oxygen, 90g water, 8.8g carbon di oxide, 7.1g chlorine. 8. If 0.2 mol of the following substances are required how many grams of those substances should be taken? Sodium chloride, magnesium oxide, calcium carbonate Project : Prepare models of various radicals using cardboard, small circular magnets and araldite. From these make models of molecules of various compounds.