Recently Active Class Vii X Chemistry Questions

In Test 502 of class 8, I got only one question wrong.The instructions said that +3 is for correct response and -1 for a wrong response.However I got 31 out of 40.How? ...

Why are Group 18 elements bigger in size than Group 17 elements? ...

Arrange HCL, CH3COOH and H3O+ in order of decreasing strength. ...

Which of the following is not a way to prevent resuting a) Painting the Iron b) Galvanization of the Iron c) Proper solidification of molten Iron d) Chemical treatment of the Iron Your Answer c Correct Answer a Your Score-1 H ...

9)What type of change occurs when we boil rice? Physical Chemical Both None Your Answer b Correct Answer a Your Score-1 How is this possible? Please check the real answer. ...

An atom of one element A has four elements in its outermost shell, and that of B has six electrons in the outermost shell. The formula of the compound formed by these two will be A2B AB2 A2B3 A3B2 Your Answer d Correct Answer ...

2)An atom X is represented as follows . The numbers of protons, electrons and neutrons in this atom are: a.21, 21, 24 b.21,21,23 c.20,20,24 d.20,20,23 Your Answer a Correct Answer b Your Score -1 How is that possible? Please ...

Why do elements like iron, nitrogen, phosphorus or copper have variable valencies? Thanks to the person who can help me in advance. Thanks, Bye, Angikar ...

Give reasons why equal volumes of nitrogen and ozone under same conditions of temperature and pressure have different number of atoms. ...

2)0.001 g of C is required to write a letter with a graphite pencil. The total number of C atoms used in writing the letter is 5 x 1012 5 x 1019 5 x 1024 1 x 1020 Your Answer Not Attempted Correct Answer b please show me the ...

If 1021 molecules are removed from 200 mg of CO2 then the number of moles of CO2 left is 2.88 x 10-3 1.66 x 10-3 4.54 x 10-3 1.66 x 10-2 Your Answer Not Attempted Correct Answer a please show me the calculation. ...

From the metals Mg and Fe, select a different metal in each case- a) Does not react with dil hydrochloric acid b) Does not react with cold water but reacts with steam when heated.... This question came in my school chemistry ...

What is the process used to make ammonia? ...

http://www.chacha.com/question/is-lead-hydroxide-amphoteric claims lead hydroxide to be amphoteric. So, what prevents it from reacting with the base ammonium hydroxide? Thanx in advance... ...

Choose the odd one out and give reasons for your answer : Propene,Ethene,1-Butene,2-Butene I choose Ethene as the odd one out because it has no isomers,while the others have atleast 1 isomer. Was I right in my prediction? If ...

Can two electrons in the same orbital of the same sub-shell of the same energy state have the same energy? Or does different spin affect the energy of an electron?? ...

Is there any way of controlling radioactivity of an element apart from making an isotope with greater number of neutrons? If yes, what? ...

What is thermal De-Broglie wavelength??? Please give a simple explanation. ...

to get pure aluminium we use the process "electrolysis refining" or hoope's electrolysis....can some1 plain it to me...its quite confusing.... ...

What is the core difference between "brazing" and "soldering"..??? They are almost the same processes... ...

As far as I know, we ourselves are electromagnetic radiations with extremely high frequency. Also, the penetration power of an EM radiation increases with its frequency, right. So, why cant we pass through an aluminium foil? ...

Alright,I am facing a problem recently. In questions where it is said name the products of the following reactions(which are generally organic ones) do we have to just write the name or formula or both? And do we have to writ ...

As far as I know, if something is mass less, it travels with speed of light and if it has mass, it cannot reach the speed of light. According to De Broglie's equation, photons do have mass but yet they travel at the speed of ...

why and how is D2O used as a moderator in nuclear reactors??? ...

what is exactly meant by tempering and how does it occur??? ...

The half life of Uranium is 2.5 x 105 yrs.In how many years 75% of the original amount of Uranium will be disintegrated? (a)105 yrs (b)30 yrs (c)3 x 2.5 x 105 yrs (d)2 x 2.5 x 105 yrs ...

why is it said that a better and uniform crystallisation is obtained if a crystal is already placed in the solution,which when cooled crystallises and deposits on the crystal....???is it due to cohesion or something???please ...

what is the difference between "Hydrogen Bond" and "covalent Bond"...???....like water is a hydrogen bond but not a covalent bond.... ...

pH depends upon the temperature....how??????....it is somewhat related to the no. of the H+ ions per mole.....may be... plzz...explain... ...

What is PET in pet bottles ? Pet as in animal,because the bottle is easy to carry Poly ethene three Poly ethene Tetrapthalate None of thse Your Answer c Correct Answer b HOW IT IS POSSIBLE? ...