Posts Tagged ‘cbse’

How was CBSE Chemistry Exam 2016?

How was the CBSE Chemistry exam 2016?

It was reported by various agencies that this year’s (2016) exam was the toughest compared to last 5 years question paper. Is it true? Was the question paper really a hard nut?IMG-20160310-WA0005

How much do you expect in   CBSE Chemistry theory paper?

Subscribe by Email

Be the first to comment - What do you think?  Posted by admin - March 9, 2016 at 1:13 pm

Categories: AISSCE CHEMISTRY   Tags: , , ,

Advantages of synthetic detergents over soaps

Synthetic detergents have several advantages over soaps.

  1. Synthetic detergents can be used even in hard water whereas some of the soap gets wasted if the water is hard.
  2. Synthetic detergents can be used even in acidic medium as they are the salts of strong acids and are not decomposed in acidic medium.
  3. Synthetic detergents have a stronger cleansing action than soaps.
  4. Synthetic detergents  are more soluble in water than soaps.
  5. Synthetic detergents are prepared from the hydrocarbons obtained from petroleum. This saves vegetable oils which are otherwise used for making soaps

Be the first to comment - What do you think?  Posted by admin - February 12, 2014 at 9:06 pm

Categories: AISSCE CHEMISTRY, CBSE Chemistry, CHEMISTRY IN EVERYDAY LIFE   Tags: , , , ,

Class 12 CBSE Chemistry Test Paper

1

Blood cells collapse when suspended in saline water. Account for it.

(1)

2

Name any two neutral oxides.

(1)

3

a) What is the principle behind reverse osmosis?

b) Which substance is usually added into water in the car radiator to act as antifreeze?

(2)

4

State Raoult’s law for a solution containing non-volatile solute.

(2)

     

5

Complete the following equations and also balance them.

i) NH4Cl + Ca(OH)2 clip_image002

ii) Zn + HNO3 clip_image004

iii) P4 + SOCl2clip_image004[1]

iv) MnO4 + HClclip_image006

(2)

6

Draw the structures of the following compounds.

i) Peroxodisulphuric acid

ii) Phosphorous acid and account for the basicity of phosphorous acid.

(2)

7

45 g of ethylene glycol ( C2H6O2) is mixed with 600g of water. Calculate (a) the freezing point depression and (b) the freezing point of the solution.

(3)

8

2 g of benzoic acid (C6H5COOH) dissolved in 25 g of benzene shows a depression in freezing point equal to 1.62 K. Molal depression constant for benzene is 4.9 K Kgmol-1. What is the percentage association of acid if it forms dimer in solution?

(3)

9

Arrange the following in the order indicated.

i) MF, MCl, MBr, MI – Decreasing ionic character.

ii)HOCl, HOBr, HOI – increasing acidic strength

iii)NH3, AsH3, SbH3, PH3 – Decreasing bond dissociation enthalpy

(3)

10

Give reasons for the following observations.

i)Halogens are strong oxidizing agents

ii)Noble gases have large positive electron gain enthalpy.

iii)Sulphur shows paramagnetic character in vapour phase.

(3)

11

How do you prepare XeO3 from XeF4? Write equation. Draw the structure of XeF6. Mention any two applications of He gas.

(3)

12

i) How is O3 estimated quantitatively?

ii)H2SO4 is a moderately strong acid. Give evidence.

ii)Though N2 exhibits +5 oxidation state, it doesnot form pentahalide. Why?

iv)Mention the conditions required for the maximum yield of NH3.

v)What happens when Cl2 reacts with excess NH3 and NH3 reacts with excess Cl2. Give equations.

(5)

13

i) With the help of a graph explain positive deviation.

ii)The vapour pressure of pure liquids A & B are 450 & 700mm Hg respectively at 350K. Find out the composition of the liquid mixture if total vapour pressure is 600mm Hg. Also find the composition of the vapour phase.

(5)

Be the first to comment - What do you think?  Posted by admin - March 13, 2012 at 7:57 am

Categories: AISSCE CHEMISTRY, CBSE Chemistry, Chemistry Model Papers, Chemistry Sample Papers, OLD QUESTION PAPERS, Question bank   Tags: , ,

CBSE Class XI Chemistry Unit Test (First Term)

1

Express the following in the scientific notation:

a) 0.000456 b) 500.0

(1)

2

Name the experiment which is used to find the charge of an electron & what is the charge of an electron?

(1)

3

What are the drawbacks of Rutherford’s atomic model?

(1)

4

Round up the following up to three significant figures.

a) 46.216 b) 10.4107 c) 0.04597 d) 2808

(2)

5

Calculate the number of atoms in the following;

a) 52 moles of Ar b) 52g of He.

(2)

6

What is the SI unit of mass? How is it defined?

(2)

7

State law of multiple proportion with an example.

(2)

8

The density of 3M solution of NaCl is 1.25g/ml. Calculate molality of the solution.

(2)

9

Define isobars with examples.

(2)

10

Mention the two developments which played a major role in the formulation of Bohr’s model of an atom.

(2)

11

The atomic number and mass number of Calcium are 20 & 40 respectively. Find out the number of electrons, protons and neutrons in a Ca2+ ion.

(2)

12

a) How many seconds are there in 3 days?

b) A jug contains 5L of milk. Calculate the volume of milk in m3.

(3)

13

Calculate the concentration of HNO3 in moles per litre in a sample which has density 1.41g/ mL & the mass percent of nitric acid in it being 69%.

(3)

14

A compound contains 4.07% Hydrogen, 24.27 carbon and 71. 65% chlorine. Its molar mass is 98.96g. What is the empirical formula of the compound?

(3)

15

Write notes on Thomson’s plum pudding model of atom with its important features.

(3)

16

What are the conclusions drawn by Rutherford in his gold foil experiment?

(3)

17

i) Define limiting reagent.

ii) 50.0kg of N2 (g) and 10.0kg of H2 (g) are mixed to produce NH3 (g). Calculate the NH3(g)

produced. Identify the limiting reagent in this reaction.

(1+4)

Be the first to comment - What do you think?  Posted by admin - at 7:55 am

Categories: AISSCE CHEMISTRY, CBSE Chemistry, Class XI Chemistry   Tags: , , ,

CBSE Chemistry Class 11 (Mid Term Exam Model Paper)

CLASS:XI CHEMISTRY

Duration: 3 hrs Maximum marks: 70

General Instructions:

All questions are compulsory.

i)Marks for each question are indicated against it.

ii)Question numbers 1 to 8 are very short answer questions and carry 1 mark each.

iii)Question numbers 9 to 18 are short answer questions and carry 2 marks each.

iv)Question numbers 1 9 to 27 are also short answer questions and carry 3 marks each.

v)Question numbers 28 to 30 are long answer questions and carry 5 marks each.

vi)Use logarithm tables if necessary. Use of calculator is not allowed.

Questions:-

1 Calculate the number of moles in 14g of N2 molecule. (1)
2 What would be the IUPAC and symbol for the elements with atomic numbers 121 and 113. (1)
3 Draw the Lewis dot structure of Nitrite ion (NO2). (1)
4 What do you meant by bond length? (1)
5 Define coefficient of viscosity. What is its S.I. unit? (1)
6 Calculate the oxidation number of phosphorous in H3P2O7and Au in HAuCl4. (1)
7 How the presence of H ions be confirmed in ionic hydrides? (1)
8 What do you understand by the term hydrogen economy ? (1)
9 Chlorine is prepared in the laboratory by treating MnO2 with aqueous HCl according to the reaction:

clip_image001[4]4HCl(aq) + MnO2 (s) 2H2O (l) + MnO2(aq) + Cl2(g)

How many grams of HCl react with 5.0 g of MnO2?

(OR)

clip_image002[6]Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the reaction, CaCO3 (s) + 2HCl(aq) CaCl2 (aq) + CO2 (g) +H2O (l).

What mass of CaCO3 is required to react completely with 25ml of 0.75 M HCl?

Atomic mass of Mn=25,Ca=20 Read more…

Be the first to comment - What do you think?  Posted by admin - at 7:48 am

Categories: CBSE Chemistry, Chemistry Model Papers, Chemistry Sample Papers, Class XI Chemistry, OLD QUESTION PAPERS   Tags: , , , ,

Next Page »