Thursday, December 20, 2012

QUESTION BANK: Atoms and & Molecules SA- 2

Q.1) Write down the names of compounds represented by the following for mulae:
(a)Al2O3                            (b) Ca3 (PO4)
(C)K2So4                                        (d) Na2S                                   
Q.2) Calculate the number of molecules present in 0.5 mol of water.
Q.3) Calculate the mass of one atom of hydrogen atom.
Q.4) what is formula mass? Calculate formula mass of NaCl.
Q.5) Calculate the number of molecules present in
(A) 0.9g of water          (b) 1.7g of ammonia
Q.6) An element ‘Z’ forms the following compound when it reacts with hydrogen, chlorine, oxygen and phosphorous.
              ZH3, ZCl3, Z2O3, and ZP
(a)What is the valence of element ‘Z’?
 (b)Element’Z’ is a metal or non-metal?
Q.7) An element ‘X’ has a valency 3(+)
(a) Write the formula of its phosphide.
(b) Write the formula of its carbonate.
  Q.8)  which of the following are tri-atomic and tetra- atomic molecules.
  CH3cl, Cacl2, NH3, Pcl3, P2O5, H2O, C2H5OH.
Q.9) Calculate the formula mass of Sodium Carbonate (NA2CO3.10H2O)
Q.10) Write the formula of the compounds formed by the following ions.
(a) Cr3+ and SO42-                         (b) Pb2+ and NO31-
Q.11) Calculate the mass per cent of each element of sodium chloride in one mole of it.
Q.12) how many (a) molecules (b) hydrogen atoms (c) oxygen atoms are there in 0.5 mol of water?
Q.13) A sample of ammonia weighs 3.00g. What mass of sulphur trioxide contains the sample number of molecules as are in 3.oog ammonia?
Q.14) how will you define the following?
(A) Atom                     (B) Atomic Mass
(C) Molecular mass
Q.15) Write the molecular formulae of all the compounds that can be formed by the combination of following ions
Cu2+, Na+, Fe3+, Cl-, SO42-, PO4     
Q.16) The visible universe is estimated to contain 1022. How many moles are present in the visible universe?
Q.17) Calculate the mass percent of each element present in the molecule of calcium carbonate.
Q.18) Verify by calculating that
(a) 5 moles of CO2 and 5 moles of H2O do not have the same mass.
(b) 240g of calcium and 240g of magnesium elements have a mole ratio of 3:5.
Q.19) Find the ratio by mass of the combining elements in the following:
(a) CaCO3                                         (b) Mgcl2
(c) H2SO4                          (d) C2H2OH
(e) NH3                                        (f) Ca (OH) 2
Q.20) Write the formulae for the following and calculate the molecular mass of each one of them.
(a) Caustic potash            (b) Baking powder
 (c) Lime stone                 (d) Caustic soda
 (e) Ethanol                       (f) Common salt
Q.21) How many moles are present in 4g of sodium hydroxide.
Q.22) Calculate the number of electrons and neutrons present in the nucleus of an element ‘Z’ which is represented as 31Z15.
Q.23) Calculate the number of moles present in 3.011 x 1023.
Q.24) Calculate the molecular mass of the following
(a) H2CO3          (b) C2H5OH       (c) H2SO4
Q.25) Write the chemical formula and chemical name of the following compounds.
(a) Baking powder          (b) Quick lime
(C) Washing soda
Q.26) Give three significance of mole.
Q.27) Calculate the number of particles in each of the following.
(a) 46g of Na atom      (b) 8g of O2 molecules
(c) 0.1 moles of carbon atom
Q.28) which of the following symbols of elements are incorrect? Give their correct symbols.
(a)Cobalt           CO                  (b) Carbon      c
(c)Aluminum     AL                  (d) Helium       He
(d)Sodium        So
Q.29) Cinnabar (HgS) is a prominent ore of mercury. How many grams of mercury are present in 225g of pure HgS? Molar mass  of Hg and S are 200.6mol-1  and 32 g mol-1, respectively.
Q.30) A sample of vitamin C is known to contain 2.58 x 1024 oxygen atoms. How many moles of oxygen atom are present in the sample?
Q.31) Raunak took 5 moles of carbon atom in a container and krish also took 5 moles of sodium atoms in container of same weight.
(a) Whose container is heavier?
(b) Whose container has more number of atoms?
Related post to IX(9th)  Atoms and Molecules

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