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castortr0y [4]
4 years ago
9

Help! What did I do wrong??

Chemistry
1 answer:
iogann1982 [59]4 years ago
4 0

The molecules  of hydrogen gas that are  formed is  when 48.7 g  of sodium are added to water  is  6.375  x 10²³  molecules


  <u><em>calculation</em></u>

2 Na +2H₂O →  2 NaOH  +H₂

Step 1: find the moles  of sodium (Na)

moles =mass÷   molar mass

from periodic table the molar mass of Na = 23 g/mol

moles= 48.7 g÷ 23 g/mol =2.117 moles

Step 2:use the mole ratio to determine  the  moles of H₂

  from  given equation  Na:H₂ is 2:1

therefore the moles  of H₂ = 2.117 moles x 1/2=1.059 moles

Step 3: find the molecules of H₂ using the Avogadro's law

According  to  Avogadro's  law  1 mole = 6.02 x 10²³ molecules

                                                      1.059 moles = ?  molecules

by cross multiplication

= [(1.059 moles x 6.02 x10²³  molecules) /  1 mole] =6.375  x 10²³  molecules

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Answer:

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Explanation:

We'll begin by converting 350 mL to L. This can be obtained as follow:

1000 mL = 1 L

Therefore,

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2.75 = Mole of KC₂H₃O₂ / 0.35

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Mole of KC₂H₃O₂ = 2.75 × 0.35

Mole of KC₂H₃O₂ = 0.9625 mole

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Mole of KC₂H₃O₂ = 0.9625 mole

Molar mass of KC₂H₃O₂ = 39 + (12×2) +(3×1) + (16×2)

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= 98 g/mol

Mass of KC₂H₃O₂ =?

Mass = mole × molar mass

Mass of KC₂H₃O₂ = 0.9625 × 98

Mass of KC₂H₃O₂ = 94.325 g

Thus, the mass of KC₂H₃O₂ needed to prepare the solution is 94.325 g

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