Thursday, October 6, 2011

Class 9, NCERT (CBSE) Science (Chemistry) - Atoms ...

Class 9, NCERT (CBSE) Science (Chemistry) - Atoms ...Q.1: Select the ionic compound -
(a) Sulphur molecule, S8 (b) Phosphorous molecule, P4
(c) Methane, CH4 (d) Copper nitrate, Cu(NO3)2  
Q.2: Which of the following does not change when a chemical reaction takes place?
(a) volume (b) mass (c) physical properties (d) chemical properties
Q.3: One atomic mass unit is equal to weight of -
(a) one atom of hydrogen (b) 1/16th of oxygen atom
(c) 1/12th of natural carbon atom (d) 1/12th of C-12 isotope of carbon.   
Q.4: Molecules of the following elements are made up of only one atom of that element -
(a) iron (b) sodium (c) helium (d) chlorine
Q.5: Formula unit mass is used for the mass of the following compound -
(a) CaO (b) H2S (c) CCl4 (d) CH4.................................

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