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tensa zangetsu [6.8K]
2 years ago
6

What volume, in mL, of a 0.539 M solution of NaBH4 is required to produce 0.579 g of B2H6? H2SO4 is present in excess.

Chemistry
1 answer:
Fittoniya [83]2 years ago
5 0

Answer:

70.872 mL

Explanation:

The reaction of Sodium borohydrate with sulfuric acid to form diborane is shown below as:

2 NaBH₄ + 2 H₂SO₄ = B₂H₆ + 3 H₂ + 2 NaSO₄

Given mass of B₂H₆ = 0.579 g

Molar mass of B₂H₆ = 27.66 g/mol

The formula for the calculation of moles is shown below:

moles = \frac{Mass\ taken}{Molar\ mass}

Thus, moles of B₂H₆are:

moles= \frac{0.579\ g}{27.66\ g/mol}

moles= 0.0191\ mol

From the reaction,

1 mole of B₂H₆ is produced when 2 moles of NaBH₄ react with acid.

So,

0.0191 moles of B₂H₆ is produced when 2×0.0191 moles of NaBH₄ react with acid.

Moles of NaBH₄ required = 0.0382 moles

Given, Molarity of NaBH₄ = 0.539 M

Molarity =  Moles / Volume

Volume = Moles / Molarity = 0.0382 moles / 0.539 M = 0.070872 L

Also, 1L = 1000 mL

So,

<u>Volume = 70.872 mL</u>

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Answer:

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Explanation:

You calculate the energy required to break all the bonds in the reactants.

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D/kJ·mol⁻¹:     436      498          464

\begin{array}{rcl}\Delta H & = & \sum{mD_{\text{reactants}}} - \sum{nD_{\text{products}}}\\& = & 2 \times 436 +1 \times 498 - 4 \times 464\\&=& 1370 - 1856\\&=&\textbf{-486 kJ}\\\end{array}\\\text{The enthalpy of reaction is $\large \boxed{\textbf{-486 kJ}}$}.

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Answer:

10.3 g of oxygen are formed when 26.4 g of potassium chlorate is heated

Explanation:

This is the balanced equation:

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Ratio beteween the salt and oxygen is 2:3

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26.4 g /122.55 g/m = 0.215 moles

So, this is the final rule of three:

If 2 moles of KClO₃ make 3 moles of oxygen

0.215 moles of KClO₃ make  (0.215  .3) /2 = 0.323 moles of O₂ are produced

Molar mass O₂ = 32 g/m

Moles . molar mass = mass

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4 0
3 years ago
A karyotype can be used to determine the number of ____________________ (alleles, chromosomes) in a person’s cells.
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Answer:

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Hope this helps!

Plz click the Thanks button :)

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