Ethynylmagnesium bromide

Ethynylmagnesium bromide or bis(bromomagnesium)-acetylene BrMgCCMgBr is very important Grignard reagent. It is useful in preparing disubstituted acetylene derivatives. Acetylenic Grignard reagent do not react with metal halides. They are very useful reagents for reaction with highly reactive compounds.

From Handbook of Grignard Reagents

Atomic Symbols. ( VIII Class)

Write Atomic Symbols of the following elements:

1.   Iron
2.   Lead
3.   Mercury
4.   Gold
5.   Cobalt
6.   Fluorine
7.   Radon
8.   Germanium
9.   Silicon
10. Copper

Shapes of Solids (basic)

New year Bengali Style (Netaji Subhash chandra Bose and Rabindranath Tagore along with our respectable Icons)

Lewis Symbol

Conversions

This is Fact

Don't read the word, but try to say the color of the word in which it is printed.

Albert Einstein

Two-Headed Shark Found by Fisherman

Two-Headed Shark Found by Fisherman

Recognizing a stroke

I URGE ALL MY FRIENDS TO READ & SHARE THIS; YOU COULD SAVE A LOVED ONES LIFE BY KNOWING THIS SIMPLE INFORMATION!!!Stroke has a new indicator! They say if you forward this to ten people, you stand a chance of saving one life. Will you send this along? Blood Clots/Stroke - They Now Have a Fourth Indicator, the Tongue:During a BBQ, a woman stumbled and took a little fall - she assured everyone that she was fine (they offered to call paramedics) ...she said she had just tripped over a brick because of her new shoes.

They got her cleaned up and got her a new plate of food. While she appeared a bit shaken up, Jane went about enjoying herself the rest of the evening.

Jane's husband called later telling everyone that his wife had been taken to the hospital - (at 6:00 PM Jane passed away.) She had suffered a stroke at the BBQ. Had they known how to identify the signs of a stroke, perhaps Jane would be with us today. Some don't die. They end up in a helpless, hopeless condition instead.

It only takes a minute to read this.

A neurologist says that if he can get to a stroke victim within 3 hours he can totally reverse the effects of a stroke...totally. He said the trick was getting a stroke recognized, diagnosed, and then getting the patient medically cared for within 3 hours, which is tough.

RECOGNIZING A STROKE

Thank God for the sense to remember the '3' steps, STR. Read and

Learn!

Sometimes symptoms of a stroke are difficult to identify. Unfortunately, the lack of awareness spells disaster. The stroke victim may suffer severe brain damage when people nearby fail to recognize the symptoms of a stroke.

Now doctors say a bystander can recognize a stroke by asking three simple questions:

S *Ask the individual to SMILE.

T *Ask the person to TALK and SPEAK A

SIMPLE SENTENCE (Coherently)
(i.e. Chicken Soup)

R *Ask him or her to RAISE BOTH ARMS.

If he or she has trouble with ANY ONE of these tasks, call emergency number immediately and describe the symptoms to the dispatcher.

New Sign of a Stroke -------- Stick out Your Tongue

NOTE: Another 'sign' of a stroke is this: Ask the person to 'stick' out his tongue. If the tongue is

'crooked', if it goes to one side or the other that is also an indication of a stroke.

A cardiologist says if everyone who gets this e-mail sends it to 10 people; you can bet that at least one life will be saved.

I have done my part. Will you?
They got her cleaned up and got her a new plate of food. While she appeared a bit shaken up, Jane went about enjoying herself the rest of the evening.
Jane's husband called later telling everyone that his wife had been taken to the hospital - (at 6:00 PM Jane passed away.) She had suffered a stroke at the BBQ. Had they known how to identify the signs of a stroke, perhaps Jane would be with us today. Some don't die. They end up in a helpless, hopeless condition instead.
It only takes a minute to read this.
A neurologist says that if he can get to a stroke victim within 3 hours he can totally reverse the effects of a stroke...totally. He said the trick was getting a stroke recognized, diagnosed, and then getting the patient medically cared for within 3 hours, which is tough.
RECOGNIZING A STROKE
Thank God for the sense to remember the '3' steps, STR. Read and
Learn!
Sometimes symptoms of a stroke are difficult to identify. Unfortunately, the lack of awareness spells disaster. The stroke victim may suffer severe brain damage when people nearby fail to recognize the symptoms of a stroke.
Now doctors say a bystander can recognize a stroke by asking three simple questions:
S *Ask the individual to SMILE.
T *Ask the person to TALK and SPEAK A
SIMPLE SENTENCE (Coherently)(i.e. Chicken Soup)
R *Ask him or her to RAISE BOTH ARMS.
If he or she has trouble with ANY ONE of these tasks, call emergency number immediately and describe the symptoms to the dispatcher.
New Sign of a Stroke -------- Stick out Your Tongue
NOTE: Another 'sign' of a stroke is this: Ask the person to 'stick' out his tongue. If the tongue is
'crooked', if it goes to one side or the other that is also an indication of a stroke.
A cardiologist says if everyone who gets this e-mail sends it to 10 people; you can bet that at least one life will be saved.
I have done my part. Will you?
Courtesy https://www.facebook.com/ProudToBeAnIndian.in

creativity

Super fluid Helium

Super fluid Helium has unique behavior different from other liquids  

-         It can dribble through molecule thin cracks.

     -         Climb up and over the side of a dish.

     

     -          Remains motionless when its container spun.

    

      -         Flows without friction.

                                                                                     

Human Eye and Colourful World (CBSE) Class X (Physics)

HUMAN EYE AND COLOURFUL WORLD

(Each question is of 2 marks)

Class X (CBSE) Physics

1.      Why when the sun is overheated at noon, it appears white but when the same sun is near the horizon at sunset, it appears red?

2.      Why stars twinkle at night?

3.      Why ocean is blue in colour?

4.      When we enter the dim light room from bright sunlight outside, why does it take time to see the objects clearly?

5.      How rainbow is formed?

6.      A boy uses spectacles of focal length 50cm. name the defect of vision he is suffering from.

7.      A man can read the number of distant bus clearly but he finds difficulty in reading book. What disease he is having?

8.      Astronauts observe the sky as dark instead of blue why?

9.      Why planets do not twinkle?

10.  Why is a normal eye not able to see clearly the objects placed closer than 25cm.

Heredity and Evolution (Class X) CBSE test paper

Heredity and Evolution

(All questions are of 1 mark)

1.      What are fossils?

2.      What is monohybrid cross?]

3.      Give two examples of analogous organs.

4.      What are vestigial organs?

5.      What are dominant genes?

6.      Define the term evolution.

7.      What is scientific name of Human Beings?

8.      What are allosomes?

9.      Write the scientific term used for ‘Science of Heredity and variation’.

10.  Radish and carrot are homologous or analogous structures?

11.  Write the name of different types of possible blood groups?

12.  Define F1 generation.

13.  What will be the sex of the embryo if an egg is fertilized by the sperm having 22+y composition?

14.  What is dihybrid cross?

15.  Define the term progeny.

Test paper on Periodic classification of the elements (X) CBSE

Periodic classification of the elements.

(CBSE) Class X Test

1. Write electronic configuration of C and Na.  (1)

2. The atom of an electronic configuration 2 8 8 2 belongs to which period? (1)

3. Which is more reactive F or Cl?  (1)

4. Which is bigger in size Cl/Cl^- ? (1)

5. Define the law of Octaves? (2)

6. Why elements of a same group show same valency? (2)

7. Discuss the position of H atom in a periodic table. (2)

8. Differentiate metals and non metals? (2)

9. Define modern periodic law. (2)

10.What are metalloids? Explain with example. (2)

Lewis structures of chemical compound

Draw Lewis Structure of following

1. NH₃

2. CO

3. CO₂

4. CH₄

5. HNO₃

6. HCl

Chemistry (Class X)(CBSE) Second term test paper on periodic classification of elements)

Class X (CBSE)

Second Term

 

PERIODIC CLASSIFICATION OF ELEMENTS:

 

Note: Question 1-3 are 1 mark each, Questions 4-10 are 2 marks each.

 

1.      What is general trend in atomic size as you move from left to right in a period?

2.      Why all the atoms of a period have different chemical properties?

3.      How many electrons are present in valence shell of Cl?

4.      What are the limitations of Dobernier’s classification?

5.      What are noble gases? Explain their characteristics?

6.      Write the electronic configuration of Na, O, F and C.

7.      Explain out of ‘Na’ and ‘K’ who is more electropositive in nature?

8.      Why atomic number of an element is more important than its mass number?

9.      Compare Na and K with respect to their valence, formula of their oxide and formula of their chloride.

10.  Atomic number of an element X is 17. Predict its valence and tell whether it is metal or non metal?

CBSE X (Chemistry) Second term (Test paper)

Class X

Second term

Unit: Chemical Substances –Nature and Behaviour

CARBON COMPOUNDS

(Question 1-10 are 1 Mark, Question 11-14 are 2 Marks and Question 15-18 are 3 Marks)

1.       Name the following functional group.  (–OH, -COOH)

2.       Give electron dot structure of CH₃Cl.

3.       Write formula of methanol.

4.       Draw structure of Chlorobutane.

5.       What are oxidizing agents?

6.       Name the functional group present in the compound               CH₃CH₂NH₂.

7.       What is the odour of the acetic acid like?

8.       Name the CH₃C=CH.

9.       How many C-H bonds are present in ethane C₂H₆.

10.   What is the need to denature alcohol?

11.   Give one example of substitution reaction.

12.   Draw structural formula of all isomers of hexane.

13.   Write chemical equation showing decarboxylation reaction of ethanoic acid.

14.   What are enzymes? Name the enzyme which ferments sugar cane to ethanol?

15.   What are synthetic detergents? Give example and how it is better than soap?

16.   What is homologous series? Explain with example. By how many carbon atoms and hydrogen atoms do any two adjacent homologues differ?

17.   What are esters? Write chemical equation showing formation of ester?

18.   Write  the reaction and name the products formed.

a)      Acetic acid and sodium hydroxide are heated together.

b)      Ethanol is burnt in oxygen in the presence of alkaline KMnO₄

   

Compound interest

Compound Interest

 (i)                  Find the amount and the 

             compound interest on 8000 

              at 5% p.a for 2 years.

Principal = Rs 8000/-

Rate of Interest = 5% p.a

Interest for the first year 

= 8000 x 5% x 1/100 = Rs 400

                                  

                 Amount for the first year or 

                  principal for the second year

                              = (8000 + 400) Rs = 8400 Rs

   

Interest for the second year 

= 8400 x 5% x 1/100 = Rs 420

                               Amount for the second year

                              =  (8400 + 420) Rs = 8820 Rs

                              Total Compound Interest

                              = 8820 – 8000 Rs = Rs 820  

chemistry test paper (XII) Amines, biomolecules, polymers, chemistry in every day life

TEST PAPER-CHEMISTRY

CLASS-XII

1.    Draw resonance structures of Aniline?

2.    Write Hoffman elemination reaction?

3.    Draw D-Glucose?

4.    What is muta – rotation?

5.    Explain tertiary structure of Proteins?

6.    Write defination of Enzyme?

7.    Write difference between Fibrous proteins and Globulor Proteins?

8.    Write  structure of Nylon-6?

9.    Define polymerisation?

10.  What is denaturation of portein?

11.  What is Condensation Polymerisation?

12.  What are antacids?

13.  What is Hard Water?

14.  Draw Structure of Zwitter-ion from of alpha amino acetic acid?

15.  What is translation?

If you want to solve chemistry final papers chemistry XII (CBSE) paper. Leave message or comment for sample papers.

Molecular Mass calculations

CALCULATE THE MOLECULAR MASS

S. No	Compound	Molecular mass
1.	AgCl
2.	Na2CO3
3.	H2SO4
4.	HCl
5.	CuSO4.7H2O
6.	HNO3
7.	KMnO4
8.	B2H6
9.	CaCl2
10	Ca(OH)2

Test Chapter: Sound (ICSE) (Physics)

Class : X
Board: ICSE
Chapter: Sound
Subject :Physics

1. What is an echo?
2. Give relation between frequency, velocity and wavelength.
3. Give two differences between free vibrations and damped vibrations?
4. name three factors on which the frequency of vibration of stretched string depends.
5. Why when a troop crosses a suspension bridge, the soldiers are asked to break steps.

6. Why are the stringed instruments provided with a sound box?
7. Define pitch. Draw wave of different pitches.
8. Differentiate between musical note and a pitch.
9. How is it possible to detect the filling of a bottle under a water tap by hearing the sound at a distance.
10. What is the safe limit of sound level in dB for our ears?