|
(a) Define molar mass. What are its units ? (b) Write the names of compounds represented by the following formulas : (i) K2C03 (ii) Na2SO4 (iii) Ca(HCO3)2 (iv) H2SO4
|
|
0
|
1092
|
June 30, 2016
|
|
A gas jar contains 1.7 g of ammonia gas. Calculate the following: (i) Molar mass of ammonia. (ii) How many moles of ammonia are present in the gas jar ? (iii) How many molecules of ammonia are present in the sample?
|
|
0
|
10757
|
June 30, 2016
|
|
Calculate number of atoms in 120 g of calcium and 120 g of iron. Which one has more number of atoms and how much is the difference ? (Given atomic mass of calcium - 40 u and iron = 56 u)
|
|
0
|
10838
|
June 30, 2016
|
|
(a) Calculate the mass of 0.5 mole of oxygen atoms. (b) Calculate the number of molecules of glucose present in its 90 grams (molecular mass of glucose is 180 u) (c) Calculate number of moles of water in 2 grams of water. Atomic mass of H = 1 u, O = 16 u
|
|
0
|
13933
|
June 30, 2016
|
|
With a labelled diagram describe an actimty to demonstrate "the law of conservation of mass."
|
|
0
|
15179
|
June 30, 2016
|
|
The ratio of hydrogen and oxygen in water is 1:8 by mass, find out their ratioby number ofatoms, in one molecule of water. (Atomic mass :H=1 u, 0=16u) (b) Write the formulae of the following compounds : (i) Ammonium sulphate (ii) Magnesium chloride
|
|
0
|
4043
|
June 30, 2016
|
|
The chemical formula of chloride of metal 'M' is MCI. Write the chemical formula of its chloride, bicarbonate and sulphide
|
|
0
|
1878
|
June 30, 2016
|
|
(a) Convert into mole : (i) 12 g of oxygen gas. (ii) 22 g of carbon dioxide. (b) Write the names of the compounds represented by the following formulae : (i) NaBr (ii) Al2O3 (in) ZnNO3 (iv) HCl (v) NaCl (vi) CaCO3
|
|
0
|
2224
|
June 30, 2016
|
|
Define polyatomic ions. Write an example. Calculate the formula unit mass of CaCO3. (Atomic mass ofC = 12 u, Ca = 40 u, O = 16 u) Calculate the molecular mass of the following: (i) HNO3 (it) CH3COOH (Atomic mass of H = 1 u, N = 14 u, O = 16 u, C = 12 u)
|
|
0
|
1192
|
June 30, 2016
|
|
What is meant by atomicity 1 How many different types of molecules are known on the basis of atomicity?
|
|
0
|
4659
|
June 30, 2016
|
|
Calculate the molecular mass of the following compounds: (i) NH4NO3 (ii) H2S04 (iii) Na2CO3 (iv) NaOH (v) HNO3 (vi) Al2(SO4)3
|
|
0
|
1588
|
June 30, 2016
|
|
Define mole. Give its symbol. What is the advantage of this mole concept?
|
|
0
|
2746
|
June 30, 2016
|
|
Calculate the number of atoms in : (i) 0.02 moles of carbon (ii) 30 grams of carbon (iii) 6 moles of aluminium ions
|
|
0
|
5684
|
June 30, 2016
|
|
Calculate the mass of: (a) 1 atom of carbon (b) 0.02 mole of sodium (c) 1 molecule of water
|
|
0
|
5557
|
June 30, 2016
|
|
State two main postulates of Thomson's model of an atom
|
|
0
|
2468
|
June 30, 2016
|
|
Explain the following with one example of each: (i) Atomic number (ii) Mass number
|
|
0
|
602
|
June 30, 2016
|
|
The number of electrons in the outermost L shell of an atom is 5. (a) Write its electronic configuration. (b) What is its valency and why?
|
|
0
|
3430
|
June 30, 2016
|
|
Write two differences between isobars and isotopes
|
|
0
|
5412
|
June 30, 2016
|
|
The electronic configuration of an element 'X' is 2,8,2 : (a) Find the number of electrons present in the atom of element X (b) Write the atomic number. (c) This element ‘X’ is a metal or a non-metal. (d) Find out the valency of the element X
|
|
0
|
7175
|
June 30, 2016
|
|
An ion X2- contains 10 electrons and 8 neutrons. What are the atomic number and mass number of elements X?
|
|
0
|
3521
|
June 30, 2016
|
|
If an ion M3+ contains 10 electrons and 14 neutrons. What are the atomic number and mass number of the element M?
|
|
0
|
1703
|
June 30, 2016
|
|
Which of the Na+ and He has completely filled K and L shells. Give reason to support your answer
|
|
0
|
2077
|
June 30, 2016
|
|
Mention the postulates of Neils Bohr put forth to overcome the objections raised against Rutherford's atomic model
|
|
0
|
4963
|
June 30, 2016
|
|
How Rutherford proved that positively charged particles are present in the nucleus of an atom?
|
|
0
|
1330
|
June 30, 2016
|
|
(a) What are canal rays ? Who discovered them ? What is the charge and mass of canal ray ? (b) How are the canal rays different from electrons in terms of charge and mass?
|
|
0
|
4917
|
June 30, 2016
|
|
Explain Bohr Bury rules for distribution of electrons into different shells. Write the distribution of electrons in sodium atom (Z = 11)
|
|
0
|
2430
|
June 30, 2016
|
|
Atom A has a mass number 238 and atomic number 92 and atom B has mass number 235 and atomic number 92. (i) How many protons, atoms A and B have? (ii) How many neutrons, atoms A and B have? (iii) Are atoms A and B isotopes of the same element? How?
|
|
0
|
3335
|
June 30, 2016
|
|
With the help of labelled diagram describe in brief the Rutherford's alpha particle scattering experiment. Write any three important conclusions drawn from the experiment
|
|
0
|
14130
|
June 30, 2016
|
|
State three features of the nuclear model of an atom put forward by Rutherford
|
|
0
|
6128
|
June 30, 2016
|
|
(a) Write the names of three isotopes of hydrogen. (b) State one use of isotope of uranium. (c) Isotopes of an element have similar properties. Why?
|
|
0
|
1052
|
June 30, 2016
|