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What is equivalent mass?

Posted by Namrta Namrta (May 20, 2017 1:57 p.m.) (Question ID: 5392)

  • Answers:
  • It is defined as the mass of an element/compound/ion which combines or displaces 1 part of hydrogen or 8 parts of oxygen or 35.5 parts of chlorine by mass.

    It is not always possible to apply this classic definition to determine equivalent weights of chemical entities.

    Answered by Payal Singh (May 20, 2017 3:36 p.m.)
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Find the volume of ammonia gas at NTP

Posted by Lokendra Singh Umath (May 17, 2017 6:22 p.m.) (Question ID: 5354)

differences between pure substance and mixture?

Posted by Sarthak Chauhan (May 17, 2017 5:34 p.m.) (Question ID: 5353)

  • Answers:
  • Ans.

    1. Pure Substance has the same composition and properties throughout Whereas Mixture is the combination of two or more pure substances where each substance retains its own identity.
    2. Pure substances cannot be separated into any other kinds of matter, while a mixture is a combination of two or more pure substances.
    3. A pure substance has constant physical and chemical properties, while mixtures have varying physical and chemical properties (i.e., boiling point and melting point).
    4. A pure substance is pure, while a mixture is impure.
    5. e.g: Pure water is a pure substance. It consist of only water molecules While e.g: Alcohol-water mixture, both co-exist together.
    Answered by Naveen Sharma (May 17, 2017 6 p.m.)
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Find no. of moles in 44.8 litres of CO2 at STP

Posted by Nikhil Malik (May 16, 2017 6:20 p.m.) (Question ID: 5335)

  • Answers:
  • At STP, one mole of gas has a volume of 22.4 liters.

    Given that there are 44.8 liters in this problem, which is twice as much as 22.4, there must be 2.00 moles of Carbon Dioxide COgas.

    Answered by Payal Singh (May 16, 2017 8:11 p.m.)
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Calculate the no. of atoms of the constituent elements in 53g of Na2CO3

Posted by Nikhil Malik (May 16, 2017 6:06 p.m.) (Question ID: 5334)

  • Answers:
  • Molecular mass of Na2CO3 = ( 2 × 23 ) + 12 + (3 × 16) = 46 + 12 + 48 = 106 

    Given mass of Na2CO3 = 53 g

    106 g of Na2COContain = 1 mol

    53 g of Na2CO3 Contain = {tex}{53\over 106} = {1\over 2}{/tex} mol  

     

    No of atoms of Na = {tex}{1\over 2}\times 2 \times 6.022 \times 10^{23}{/tex}{tex} 6.022 \times 10^{23}{/tex}

    No of atoms of C = {tex}{1\over 2}\times 6.022 \times 10^{23}{/tex}

    {tex}3.011 \times 10^{23}{/tex}

    No of atoms of O = {tex}{1\over 2}\times 3 \times 6.022 \times 10^{23}{/tex}{tex}9.033\times 10^{23}{/tex}

     

    Answered by Payal Singh (May 19, 2017 7:34 a.m.)
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Why metals are melleable and ductile?give sutaible reason.

Posted by Vanshika Kalra (May 16, 2017 1:04 p.m.) (Question ID: 5326)

  • Answers:
  • Metals are malleable and ductile because they are made of hexagonal and cubic packed structures that can be moved by applying force to them. When force is applied, the atoms slide from one plane past atoms in a different plane.

    Answered by Payal Singh (May 16, 2017 2:36 p.m.)
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<h1>5 differences</h1> <h1>between a pure substance and a mixture</h1>
Posted by Sarthak Chauhan (May 14, 2017 11:24 a.m.) (Question ID: 5290)

  • 5 differences between pure substance and mixture.

    Posted by Sarthak Chauhan (May 17, 2017 5:27 p.m.)
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<h1>5 differences between a pure substance and a mixture</h1>
Posted by Sarthak Chauhan (May 14, 2017 11:21 a.m.) (Question ID: 5276)

  • Please answer !!!!!

    Posted by Sarthak Chauhan (May 17, 2017 5:25 p.m.)
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What mass of carbon will be present in 342gram sample of sucrose(C12H22O11)

Posted by Lokendra Singh Umath (May 12, 2017 9:58 p.m.) (Question ID: 5266)

Find the no. Of molecules of 4.25g ammonia

Posted by Lokendra Singh Umath (May 12, 2017 9:55 p.m.) (Question ID: 5265)

  • Answers:
  • Molar mass NH3 = 14+3 = 17g/mol

    4.25g = 4.25/17 = 0.25 mol

    NH3 1mol = 6.022 {tex}\times {/tex}1023 molecules

    0.25 mol = 0.25 {tex}\times{/tex}6.022 {tex}\times {/tex}1023

    Number of molecules = 1.51 {tex}\times{/tex}1023 

    Answered by Payal Singh (May 19, 2017 6:35 a.m.)
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Find no. Of moles of.25g of ammonia

Posted by Lokendra Singh Umath (May 12, 2017 9:48 p.m.) (Question ID: 5264)

Find mass of 3g atom magnesium

Posted by Lokendra Singh Umath (May 12, 2017 8:30 a.m.) (Question ID: 5247)

  • Answers:
  • Ans. Molecular mass if Magensium = 24.3 

    So No of Atoms in 24.3 g of Magnesium = {tex}6.022 \times 10^{23}{/tex}

    No of Atoms in 1 g of Magnesium =  {tex}6.022\times 10^{23}\over 24.3{/tex}
    No of Atoms in 3 g of Magnesium = {tex}{6.022\times 10^{23}\over 24.3}\times 3{/tex} 

    {tex}0.743 \times 10^{23}{/tex}

    Answered by Naveen Sharma (May 12, 2017 9:10 a.m.)
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Find the no. Of atoms in 24g sample of C12

Posted by Lokendra Singh Umath (May 12, 2017 6:39 a.m.) (Question ID: 5246)

  • Answers:
  • Molecular Mass of 12C = 12 

    No of Atoms in  12g of 12C = 6.022 × 1023

    No of Atoms in  1g of 12C =

    {tex}{1\over 12 }\times {/tex} 6.022 × 1023

    No of Atoms in  20g of 12C =

    {tex}{20\over 12}\times {/tex}6.022 × 1023{tex}10.036 \times 10^{23}{/tex}

     

    Answered by Payal Singh (May 12, 2017 7:38 a.m.)
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Calculate the molarity of water. If density of water is 1g per ml.

Posted by Rk Kashyap (May 09, 2017 10:30 a.m.) (Question ID: 5168)

  • Please answer me fast !!!

    Posted by Rk Kashyap (May 09, 2017 10:43 a.m.)
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  • Answers:
  • Thanku very much

    Answered by Rk Kashyap (May 09, 2017 12:13 p.m.)
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  • Ans. 1 liter water =1 Kg
    or 1000 ml water = 1 Kg 

    Given density of Water (d) =1g/ml = 1kg/L

    Mass of 1 Litre of water = Density of water * Volume   =  1 * 1 = 1 Kg = 1000g 

     Moles of water present in 1L = {tex}1000\over 18{/tex} = 55.55  

    Hence Molarity of water = 55.55 M 

    Answered by Naveen Sharma (May 09, 2017 11:54 a.m.)
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How many triads doberieneir gave

 

Posted by saba Karim (May 08, 2017 10:15 p.m.) (Question ID: 5163)

  • Answers:
  • Doberieneir gave 3 triads

    • Li Na K
    • Cl Br I
    • Ca Sr Ba
    Answered by Payal Singh (May 09, 2017 7:44 a.m.)
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If the concentration of glucose(C6 H12 O6) in blood is  0.9 g/l, what will be the molarity of glucose in blood?

Posted by Garvit Khurana (May 08, 2017 9:49 p.m.) (Question ID: 5162)

  • Answers:
  • Solution

    Concentration of glucose in blood = 0.9g/L Number of moles of glucose = {tex}{0.9\over 180 } = 0.005\space moles{/tex} 

    Volume of solution = 1 litre

    Hence, Molarity = {tex}Number \space of \space moles \over Volume \space of \space solution \space in\space litres{/tex} = {tex}0.005 \over 1 {/tex}=     0.005M

    Answered by Payal Singh (May 09, 2017 7:50 a.m.)
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How much copper can be obtained from 100g of copper sulphate ?

Posted by Sapna Singh (May 07, 2017 11:47 p.m.) (Question ID: 5156)

  • Answers:
  • Ans. 1 mole of CuSO4 provides 1 mole Of Cu.

    Hence 159.5 g of CuSO4 {tex}\to {/tex} 63.5 g of Cu

    ( molar mass of CuSO4 is 159.5 and cu is 63.5)

    So 100 g of CuSOll produce {tex} {63.5\times 100 \over 159.5}{/tex}

    = 39.8g

    Answered by Payal Singh (May 08, 2017 6:28 a.m.)
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How are 0.50 mol Na2Co3 and 0.50 M Na2Co3 different?

Posted by Sapna Singh (May 07, 2017 11:45 p.m.) (Question ID: 5155)

  • Answers:
  • Here 0.50 mol of sodium carbonate refers to the number of moles whereas 0.50 M refers to the molarity of sodium carbonate.

    Answered by Payal Singh (May 08, 2017 6:29 a.m.)
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Explanation of hydrogen spectrum and equation 

Posted by Shalini Jha (May 04, 2017 8:45 a.m.) (Question ID: 5105)

Calculate lemda neu and energy for the last line of each Series 

Posted by Shalini Jha (May 03, 2017 7:26 p.m.) (Question ID: 5096)

Five properties of electromagnetic spectrum. 

Posted by Bimla Singh (Apr 27, 2017 8:17 p.m.) (Question ID: 5045)

calculate total number of oxygen atoms in container which contains 110 gram of carbon dioxide, 96 gram of ozone, 90 gram of water, 160 gram of sulphur trioxide and 342 gram of sucrose

Posted by Harmehar Malhotra (Apr 23, 2017 6:46 p.m.) (Question ID: 5016)

Which book we should prefer in class 11.

NCERT publication or private books.

Posted by prashant kumar (Apr 08, 2017 8:57 p.m.) (Question ID: 4783)

  • you should go through ncert readings and make notes [atleast 5times reading for every chapter] so that you can understand it this will help you for clearing any competative exam like jee or neet which are totally based on ncert concept,then make a doubt list during reading clear it after reading from any refrence book/ from viedos on youtube/from any cbse guide teacher/from any school teacher/tuitor.ncert is for base clearing and further refrence books are for practising questions and extra topics for competative exam.thank you

     

    Posted by manvi singh (Apr 09, 2017 1:54 a.m.)
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A vessel is transferred from a smaller vessel to bigger vessel at the same temperature what will be the effect on vapour pressure? 

Posted by Hitesh Pandey (Apr 06, 2017 11:48 a.m.) (Question ID: 4738)

what is syn gas and how it is prepared nowdays

Posted by SHIVAM JAISWAL (Mar 20, 2017 1:07 a.m.) (Question ID: 4160)

Oxidation number of N in (NH4)2 SO4

 

Posted by fazil khan (Mar 19, 2017 12:40 p.m.) (Question ID: 4108)

What is green chemistry

Posted by Khizer Ansari (Mar 17, 2017 9:11 p.m.) (Question ID: 4028)

  • Answers:
  • Ans. Green chemistry, also called sustainable chemistry, is an area of chemistry and chemical engineering focused on the designing of products and processes that minimize the use and generation of hazardous substances.

    Answered by Naveen Sharma (Mar 17, 2017 10 p.m.)
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derive the equation Kp=Kc(RT)

Posted by jay patel (Mar 17, 2017 9:20 a.m.) (Question ID: 3967)

discuss the diagonal relationship between Be and Al

Posted by jay patel (Mar 17, 2017 9:18 a.m.) (Question ID: 3966)

  • Answers:
  • Ans. The ionic radius of Be2+ is estimated to be 31 pm : the charge/ radius ratio is nearly the same as that of the Al3+ ion. Hence beryllium resembles aluminium in some ways. Some of the similarities are:

    • Like aluminum, beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal.
    • Beryllium hydroxide dissolves in excess of alkali to give a beryllate ion, just as aluminium hydroxide gives aluminate ion.
    • The chlorides of both beryllium and aluminium have Cl- bridged chloride structure in vapour phase. Both the chlorides are soluble in organic solvents and are strong Lewis acids. They are used as Friedel Craft catalysts.
    • Beryllium and aluminium ions have strong tendency to form complexes.
    Answered by Naveen Sharma (Mar 17, 2017 9:46 a.m.)
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compare the structure of water molecule and ice?

Posted by jay patel (Mar 17, 2017 9:16 a.m.) (Question ID: 3965)

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