## anonymous 4 years ago mole concept !

1. anonymous

@waterineyes back here :)

2. anonymous

3. anonymous

yea .. okay !

4. anonymous

Calculate the mass of the following : (a) 0.5 mole of CO2. (b) 6.02 * 10^21 molecules of O2. (c) 1 * 10^23 molecules of H2S. (d) 56.8 L of SO2. (e) 1.5 mole of H2SO4.

5. anonymous

I had said to write question here not questions here .. Ha ha ha.. Kidding..

6. anonymous

i don't understand .. what did you want me to do actually ?

7. anonymous

question means one question. questions means more than one questions.. Leave it.

8. anonymous

oh i din see the < S > !

9. anonymous

its one question my teacher gave !

10. anonymous

there are many questions like this .. and water will solve everything :p

11. anonymous

i hope so !

12. anonymous

Ha ha ha..

13. anonymous

:)

14. anonymous

so you know this ?

15. anonymous

Yes...

16. anonymous

so teach !

17. anonymous

For fist part: Find the molecular mass of $$CO_2$$..

18. anonymous

*first..

19. anonymous

molecular mass , mass and molar mass excluding the ( g ) all the same ?

20. anonymous

I will say not to go this way..

21. anonymous

then ?

22. anonymous

See now you have studied What is Molar Mass.. Molar mass is mass of 1 mole of any substance. If that substance is CO2 then: Molar Mass is mass of 1 mole of CO2 So here basically you have to find Molar Mass.. For getting molar mass you will find the molecular mass of CO2 first same as you did for NaCl..

23. anonymous

yeah okay .. so in the question we are asked to find the mass right ?

24. anonymous

For atoms: we have atomic mass. For molecules we have molecular mass..

25. anonymous

okay !

26. anonymous

Yes.. Molar mass is nothing but mass only. Molar Mass is "Mass" of 1 mole of a substance in grams..

27. anonymous

okay :)

28. anonymous

so how to do (a) ?

29. anonymous

mass of CO2 is 44 g ?

30. anonymous

31. anonymous

According to the definition of molar mass: Molar mass is mass of 1 mole right ??

32. anonymous

yeah !

33. anonymous

But you have to find for 0.5 mole.. This you got mass for 1 mole.. can you find? for 1 mole it is 44g for 0.5 or half it will be ??

34. anonymous

0.5 * 44 / 1 ?

35. anonymous

right ?

36. anonymous

Yep..

37. anonymous

okay :)

38. anonymous

Think logically also.. For 1 it is 44g for half that is 0.5 is nothing but half of 1: for 0.5 it will be 44/2 = 22g. Getting ??

39. anonymous

partially !

40. anonymous

yea yea .. on second thinking i understood !

41. anonymous

i forgot half of 1 is 0.5 !

42. anonymous

0.5 is 1/2 no ??

43. anonymous

yea i got it !

44. anonymous

This solves first one.. Getting ??

45. anonymous

dont laugh !

46. anonymous

yeah :)

47. anonymous

Ha ha ha ha.. Not I am not.. Ha ha ha..

48. anonymous

lol yu are !

49. anonymous

okay .. best medicine .. so laugh !

50. anonymous

e> part is same.. Can you do that ??

51. anonymous

let me try !

52. anonymous

53. anonymous

mass of 6.023 * 10^23 molecules of O2 = 32 mass of 6.02 * 10^21 molecules of O2 = x cross multiply ?

54. anonymous

Go for last part.. e) part

55. anonymous

okay !

56. anonymous

This I tell you later on..

57. anonymous

okay !

58. anonymous

e part is same as a part. Just try that so that you will completely get it..

59. anonymous

mass of 1 mole of CO2 = 44 g mass of 1.5 mole of CO2 = ? 44 * 1.5 / 1 = 66 g

60. anonymous

@waterineyes

61. anonymous

wrong ?

62. anonymous

Yes concept is right..

63. anonymous

Dear there is H2SO4 not CO2...

64. anonymous

oh .. sorry !

65. anonymous

okay let me do with H2SO4

66. anonymous

Do the same for H2SO4..

67. anonymous

I am in no hurry take your time..

68. anonymous

Atomic Mass of H is : 1 Atomic Mass of S is : 28 Atomic Mass of O is : 16..

69. anonymous

mass of 1 mole of H2SO4 = 98 g mass of 1.5 mole of H2SO4 = x = 98 * 1.5 / 1 = 147 g

70. anonymous

atomic mass of s = 32 or 28 ?

71. anonymous

@waterineyes there ?

72. anonymous

I think you are right..

73. anonymous

My mistake : Atomic Mass of Sulphur is 32..

74. anonymous

okay !

75. anonymous

Yes you have done that correctly: 98 + 49 = 147 g...

76. anonymous

okay .. :)

77. anonymous

Now we will do second part b)..

78. anonymous

okay !

79. anonymous

but i did that before right ?

80. anonymous

is that wrong ?

81. anonymous

Yes somewhat wrong..

82. anonymous

okay .. so teach me :)

83. anonymous

Sere have you remembered this: $1 Mole (oxygen) = 6.023 \times 10^{23} \; Oxygen \; \; Molecules$

84. anonymous

okay

85. anonymous

then .. how to do ? are you trying ?

86. anonymous

Oh really very sorry.. You were doing it right

87. anonymous

really ?

88. anonymous

$6.023 \times 10^{23} \implies 32g$ $1 \implies \frac{32}{6.023 \times 10^{23}}$ $6.023 \times 10^{21} \implies \frac{32}{6.023 \times 10^{232}} \times 6.023 \times 10^{21} = ??$

89. anonymous

Oh sorry there is mistake in denominator there power of 10 is 23 and not 232..

90. anonymous

okay ..

91. anonymous

There is mistake in denominator 10 has power 23 and not 232..

92. anonymous

yeah you did mention it above !

93. anonymous

so 32/100 = 0.32g ?

94. anonymous

Yes you were going right @ashna Do it in your way if you did not understand my way..

95. anonymous

no both seems the same .. i can understand :)

96. anonymous

Yep you are right..

97. anonymous

Now c part is same as b..

98. anonymous

And there is H2S not O2. Ha ha ha.. Just kidding..

99. anonymous

mass of 6.02*10^23 molecules of H2S = 34g mass of 1*10^23 molecules of H2S = x 34 * 1*10^23 / 6.02 *10^23 = 34 / 6.02 = 5.6 g

100. anonymous

yea this time my eyes are wide :P

101. anonymous

correct ?

102. anonymous

Ha ha ha.. Yes you are right.. Now tell me what is L there with 56.8 I am not getting that..

103. anonymous

In part D..

104. anonymous

liter or litre not sure with the spelling .. !

105. anonymous

Do you have answers with you for all of these??

106. anonymous

not for everything !

107. anonymous

or have your teacher given example of How for Liters we find the mass ??

108. anonymous

yes .. you want that ?

109. anonymous

yes if you can..

110. anonymous

i guess the teacher has done this in class !

111. anonymous

let me check !

112. anonymous

okay..

113. anonymous

okay she's written something like 22.4 L .. What is that ?

114. anonymous

I think I am getting that 22.4 part..

115. anonymous

okay !

116. anonymous

Can you wait for just few minutes. I am having breakfast now.. Till then check this: http://www.ausetute.com.au/moledefs.html

117. anonymous

There check: Ideal Gas Volumes Part..

118. anonymous

Getting @ashna ..

119. anonymous

YES

120. anonymous

An ideal gas has Volume = 22.4 L at STP..

121. anonymous

okay

122. anonymous

So: 1 Mole of SO2 = 22.4 L 1L = 64/22.4 56.8 L = 64/22.4 * (56.8? Right ??

123. anonymous

yes

124. anonymous

Can you do the solvation ??

125. anonymous

okay

126. anonymous

Understood ?? How to find all ??

127. anonymous

162.28 ?

128. anonymous

Yep..

129. anonymous

thank you :)

130. anonymous

Welcome dear..

131. anonymous

okay now .. next question ?

132. anonymous

I am gone.. New post please..

133. anonymous

Medal for solving c and e part. Ha haha..

134. anonymous

:P .. i have to really give you , for spending so much time with me :)

135. anonymous

you are a good human and a good teacher ;)

136. anonymous

Really? Well, I am not..

137. anonymous

what if i say you are one .. ?

138. anonymous

Then I simply: $$\color{green}{\text{Refuse}}$$

139. anonymous

and why ?

140. anonymous

I said I am not that is why.

141. anonymous

well then .. never mind , i'll have it that way :P

142. anonymous

Never will I..

143. anonymous

it is just because you are down to earth you are saying like that !

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