## ashna 3 years ago Can anyone teach me mole concept .. please ?

1. waterineyes

I am in a doubt from where should I start.. Firstly tell me what you know about Mole concept till now?? Don't worry just tell me what you know about this ??

2. ashna

to be frank i dont know anything , this is my new chapter . the teacher taught something but nothing did enter my brain , my only hope is you now , teach my like how yu teach first grader .. please , having my test this wednesday !

3. waterineyes

4. waterineyes

See, to measure any quantity you will need a suitable measure for it.. Right??

5. ashna

yes

6. waterineyes

Say for example: You have 12 bananas.. So for simplicity or measuring it you say it is 1 dozen. 12 bananas = 1 Dozen So, here you have measured 12 bananas by saying 1 Dozen of bananas.. Getting ??

7. ashna

yea .. getting it :)

8. waterineyes

Now you know in even a small substance or quantity, there are very large number of atoms and molecules.. These atoms and molecules are very small so in even in a very small quantity they are present in very large amount.. Getting this ??

9. ashna

yea got it !

10. waterineyes

So, here If I want to measure these atoms and molecules I need a suitable measure for it too so that I can measure or define these large numbers of atoms or molecules with ease.. So for that we need Mole Concept.. Got this??

11. ashna

yea .. thanks water , you dont teach lyk how my teache did :D

12. waterineyes

Insulting me?? Ha ha ha.. Never mind..

13. waterineyes

Wanna proceed further ??

14. ashna

hey am nt insulting ,i meant to say you were teaching very wel and nothing like how my teacher did .. of course .. please proceed !

15. waterineyes

I was just kidding @ashna

16. ashna

:)

17. waterineyes

You should remember this : Basically, we use idea of mole or Mole concept to count at the Microscopic Level.. By Microscopic Level, we mean very small particles like atoms, molecules, electrons, ions etc.. These are counted in Microscopic Levels. Getting the wordings here ??

18. waterineyes

*to count entities..

19. ashna

yea getting :)

20. waterineyes

So now we will define What Mole is..

21. ashna

okay !

22. waterineyes

This is the book definition of Mole.. you can check in your book..

23. ashna

one mole = 6.023 * 10^23 molecules ?

24. waterineyes

Yes but its the value.. I am talking about definition..

25. ashna

oh okay .. !

26. waterineyes

$$\color{blue}{\text{Mole}}:$$ One Mole is the amount of a Substance that contains as many particles (entities) as there are atoms in exactly $$12 \;grams$$ of the $$^{12}C$$ isotope.

27. waterineyes

This is book definition.. I explain you best to my knowledge..

28. waterineyes

There $$C$$ is Carbon..

29. ashna

okay !

30. waterineyes

@ashna , do you know for measuring any quantity we keep some standards for measuring any quantity..

31. ashna

like fore mass , kg ?

32. waterineyes

Close to it.. I explain you.. For mass it is kg.. But we should make some standards which will define what kg is.. We first make standards for kg so that we can say this much amount is kg.. So that whole world can follow the same..

33. ashna

yeah okay !

34. waterineyes

That is called Standardization of something. For length it is meters of course.. but we will standardize the meter.. Suppose this will create problem if I say 100cm is 1 meter and you will say no 200 cm is 1 meter.. In that case we will fight.. Right ??

35. ashna

yeah .. we will :P

36. waterineyes

So to standardize the Mole we measure all the atoms in 12 grams of Carbon and the result we got from that we call it as one mole..

37. ashna

wow .. i understood :D

38. ashna

then .. ?

39. waterineyes

Okay..

40. waterineyes

Now we will find its value and define Avagadro's Number.. Heard the name ??

41. ashna

yeah !

42. waterineyes

I am just telling you but if you want then you can leave it too: By using a device called "Mass Spectrometer" (used to find Mass) physicists calculate the MASS OF ONE ATOM OF CARBON ($$^{12}C$$) to be: $\large 1.992648 \times 10^{-23} \; g$

43. waterineyes

Do you know the Atomic Mass of Carbon ??

44. ashna

oh .. never heard of that , ty :)

45. ashna

12 ?

46. waterineyes

Yep..

47. ashna

okay !

48. ashna

then ?

49. waterineyes

So we calculate the value of mole by using: $Number \; \; of \; \; Atoms = \frac{Mass}{Mass \; of \; One \; Atom}$

50. waterineyes

You can say 1 Mole also in place of Number Of Atoms.. $\large 1 \; Mole = \frac{12}{1.992648 \times 10^{-23}}$

51. ashna

understood !

52. waterineyes

You can say 1 Mole also in place of Number Of Atoms.. $\large 1 \; Mole = \frac{12}{1.992648 \times 10^{-23}}$ $\large 1 Mole = 6.023 \times 10^{23}$

53. ashna

okay .. can you tell me the difference between mole and molecules ?

54. waterineyes

Mole is a measuring quantity.. Molecule is like formed by atoms.. $O_2$ this is molecule.

55. ashna

okay !

56. waterineyes

This is called Oxygen Molecule..

57. waterineyes

Actually mole will contains molecules. Suppose 1 mole will contains 6.023*10^{23} molecules of Oxygen..

58. waterineyes

*will contain..

59. ashna

so you mean 1 C and 1 O contains same number of molecules ? or is it the same for all elements ?

60. waterineyes

Just similar to : 1 Dozen will contain 12 Bananas. 1 Mole will contain 6.023*10^{23} molecules..

61. ashna

okay !

62. waterineyes

Yes coming to your question right now..

63. waterineyes

See if you are talking about atoms then 6.023*10^{23} atoms.. If you are talking about molecules then 6.023*10^{23} molecules.. I give you example have patience..

64. ashna

okay :)

65. waterineyes

1 Mole of Hydrogen Atoms = $$6.023 \times 10^{23}$$ hydrogen atoms. 1 Mole of Water Molecules = $$6.023 \times 10^{23}$$ water molecules..

66. ashna

okay

67. waterineyes

1 Mole of Carbon Atoms = $$6.023 \times 10^{23}$$ Carbon atoms. 1 Mole of Oxygen Atoms = $$6.023 \times 10^{23}$$ Oxygen atoms..

68. ashna

yeah .. now i can understand :)

69. waterineyes

70. ashna

is that tough ?

71. waterineyes

1 Mol is given other name as "Avagadro's Constant" So: $$6.023 \times 10^{23}$$ is the value for :Avagadro's Constant".. Avagadro's Constant is denoted by $$N_A$$; So: $N_A = 6.023 \times 10^{23}$

72. waterineyes

Is this tough?? Ha ha ha

73. ashna

why laughing ?

74. waterineyes

My habbit..

75. ashna

you got brains .. and my brains have just started developing .. that too after entering into open study !

76. waterineyes

No I did not mean that @ashna ..

77. ashna

i dont like chem , phy or math .. am only into literature !

78. ashna

oh god .. am not making you feel or anything .. am just talking naturally .. am sorry if you felt for it !

79. waterineyes

Literature?? Great.. Here Literature section is also there. You can spend your time there also..

80. ashna

i know :)

81. ashna

Na means ?

82. waterineyes

It is denotion for Avagadro's constant..

83. waterineyes

I mean you can represent Avagadro's Number or constant as: $Avagadro's \; Constant = N_A = 1 Mole = 6.023 \times 10^{23}$

84. ashna

okay .. and may i know if it is 10^22 or 10^23 or both ?

85. waterineyes

Not both: only 23..

86. waterineyes

I am using 23 everywhere..

87. waterineyes

$\huge 1 Mole = 6.023 \times 10^{23}$

88. ashna

scroll up and see what you wrote for avagadros constant 1

89. waterineyes

1 Mol is given other name as "Avagadro's Constant" So: $$6.023 \times 10^{23}$$ is the value for :Avagadro's Constant".. Avagadro's Constant is denoted by $$N_A$$; So: $$N_A=6.023×10^{23}$$ Here ??

90. ashna

yea ..

91. ashna

is it 22 for avagadro's constant ?

92. waterineyes

Where I have written 22 then ??

93. waterineyes

No..

94. waterineyes

It has the same values as 1 Mole has...

95. ashna

*10^23 ? is what you have written ?

96. ashna

looks like 22 to me .. its okay , next week ll hav eye check up .. you continue :)

97. waterineyes

Yes.. Right click on that then select Show Math As and then text commands if you want to confirm..

98. ashna

its okay .. i trust you ;)

99. waterineyes

What I can explain more in this ?

100. waterineyes

Do you know about Molar Mass ??

101. ashna

teach me how to do the sums !

102. waterineyes

Ha ha ha... My weakest part..

103. waterineyes

Do you know what is molar mass ??

104. ashna

what is molar mass .. ?

105. ashna

some problem with my net connection .. that's why i seemed offline sorry !

106. ashna

am sorry again !

107. waterineyes

See @ashna I am helping you and I had studied these 5 years ago I am not good at these but I am seeing what I can do this for you in this. Don't say sorry it is okay..

108. waterineyes

And we have other members too so don't worry we are on safe side..

109. ashna

okay .. but i prefer you .. u've been the one who has been helping me from the begining in OS !

110. ashna

what is molar mass ?

111. waterineyes

Molar Mass is: See once you have found 1 Mole of any substance then Mass of that 1 Mole of substance in grams in called Molar Mass..

112. ashna

okay .. partly understood .. examples in stock ?

113. waterineyes

This is my wording not according to the book: According to the book definition: Molar Mass: The Mass of one Mole of a substance in grams is called Molar Mass.. I give you example..

114. ashna

okay !

115. waterineyes

Can you tell me molecular mass of Water ??

116. ashna

i dont know !

117. waterineyes

$$H_2O = 2 \times 1 + 16 = 18$$

118. ashna

oh okay !

119. waterineyes

there are two H: H has mass equal to 1. So 2 H's will have 2 there is one O: oxygen has 16 as its mass: 16 2 + 16 = 18 Have you studied about molecular mass ?/

120. ashna

if this is called molecular mass.. then yes , some basics in my 8th !

121. ashna

am not sure with the names !

122. waterineyes

Remember : This is called Molecular Mass..

123. ashna

okay !

124. ashna

you ask me the molecular mass of something.. let me try !

125. waterineyes

Then Molar Mass is simple just very simple: Molar Mass = 18 grams..

126. ashna

oh .. just write it in terms of g ?

127. waterineyes

Find the molecular mass of Sodium Chloride (Salt). Do you know symbolically what is it ??

128. ashna

nacl ?

129. waterineyes

Yes can you find its molecular mass ?/

130. ashna

let me try !

131. waterineyes

I am attaching here some flash file hope you will like it..

132. ashna

atomic mass of Na is 23 atomic mass of Cl is 35.5 add them both ?

133. waterineyes

I will send you by other means it will take time to upload here.. Yes add them both..

134. ashna

okay !

135. ashna

58.5

136. ashna

molar mass 58.5g ?

137. waterineyes

yep..

138. ashna

:)

139. waterineyes

Can you give me the question on mole concept so that I can explain you how to do it.. I am unable in finding it..

140. waterineyes

Wait. This has gone long. Start a new post..

141. ashna

okay :)

142. waterineyes

I mean to say that can we start a new post @ashna

143. ashna

yea okay !

144. waterineyes

Medal for finding molecular mass of NaCl..

145. ashna

lol .. thanks :)