Sodium borohydride, NaBH 4 , a substance used in the synthesis of many pharmaceutical agents, can be prepared by reaction of NaH with B 2 H 6 according to the equation 2 NaH + B2H 6 → 2 NaBH 4 (a) How many grams of NaBH 4 can be prepared by reaction between 8.55 g of NaH and 6.75 g of B 2 H 6 ?

Hey everyone. So for this problem, we need to find the mass of a L 203 that forms an aluminum and oxygen react were given our balanced chemical equation so we can jump right into this to find the limiting reactant, we'll do 128 .7g of aluminum. And we need to multiply it by aluminum's molar mass conversion. So we have one mole of aluminum Is about 27 g of aluminum. Then we need to multiply it by the multiple ratio between aluminum and L 203. So for every four moles of aluminum, we have two moles of a L 203, so two moles A L 203. We have four moles of aluminum. When you solve that out, you'll find we have about 2.38 moles Of a little 203 That can be formed from 128.7 g of of aluminum. So we're going to do the same thing with oxygen. We have 183.55 g of oxygen And again multiplied by oxygen's Mueller mass conversion. So for one mole of oxygen, we have about 32 g of oxygen. Again, we want to multiply it by our multiple ratio. So we have three moles of oxygen for two moles, ale 203. So two moles A L for three moles of oxygen. When you solve this out, you'll find we have 3.82 moles of a L 203 things are formed. So are limiting reactant here is going to be aluminum because only 2. moles of a L 203 reformed from that. So all we need to do now is to convert that to 2030.38 g. So we have 2.38 moles of a L 203 And we need to multiply it by its moles to g conversion. So for every 102g of a L 203, we have one mole Of A L 203. When you solve this out, we're left with 2 42.76 g of a L 203. This is going to be our answer to this problem. I hope this video helped you out and I'll see you in the next one.

Ch.3 - Mass Relationships in Chemical Reactions

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McMurry 8th Edition

Ch.3 - Mass Relationships in Chemical Reactions

Problem 85a

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Chapter 3, Problem 85a

Sodium borohydride, NaBH₄, a substance used in the synthesis of many pharmaceutical agents, can be prepared by reaction of NaH with B₂H₆ according to the equation 2 NaH + B2H₆ → 2 NaBH₄
(a) How many grams of NaBH₄ can be prepared by reaction between 8.55 g of NaH and 6.75 g of B₂H₆?

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Calculate the molar mass of NaH and B_2H_6 using the atomic masses of Na, B, and H.

Convert the given masses of NaH and B_2H_6 to moles by dividing by their respective molar masses.

Determine the limiting reactant by comparing the mole ratio of NaH to B_2H_6 from the balanced equation with the moles calculated.

Use the moles of the limiting reactant to calculate the moles of NaBH_4 produced, based on the stoichiometry of the balanced equation.

Convert the moles of NaBH_4 to grams by multiplying by its molar mass.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows chemists to predict how much of each substance is consumed or produced based on balanced chemical equations. In this case, understanding the stoichiometric coefficients from the reaction equation is essential to determine the limiting reactant and calculate the mass of NaBH4 produced.

Limiting Reactant

The limiting reactant is the substance that is completely consumed first in a chemical reaction, thus determining the maximum amount of product that can be formed. Identifying the limiting reactant is crucial for accurate calculations in stoichiometry, as it dictates how much of the product can be produced from the available reactants. In this question, one must compare the moles of NaH and B2H6 to find which one limits the formation of NaBH4.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is essential for converting between the mass of a substance and the number of moles, which is necessary for stoichiometric calculations. In this problem, calculating the molar masses of NaH and B2H6 will enable the conversion of the given masses into moles, facilitating the determination of the limiting reactant and the amount of NaBH4 produced.

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Molar Mass Concept

Related Practice

The reaction of tungsten hexachloride (WCl₆) with bismuth gives hexatungsten dodecachloride (W₆Cl₁₂).

WCl₆ + Bi → W₆Cl₁₂ + BiCl₃ Unbalanced

(a) Balance the equation.

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Textbook Question

The reaction of tungsten hexachloride (WCl₆) with bismuth gives hexatungsten dodecachloride (W₆Cl₁₂).

WCl₆ + Bi → W₆Cl₁₂ + BiCl₃ Unbalanced

(b) How many grams of bismuth react with 150.0 g of WCl₆?

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Textbook Question

The reaction of tungsten hexachloride (WCl₆) with bismuth gives hexatungsten dodecachloride (W₆Cl₁₂).

WCl₆ + Bi → W₆Cl₁₂ + BiCl₃ Unbalanced

517

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Textbook Question

Sodium borohydride, NaBH₄, a substance used in the synthesis of many pharmaceutical agents, can be prepared by reaction of NaH with B₂H₆ according to the equation 2 NaH + B2H₆ → 2 NaBH₄

(b) Which reactant is limiting, and how many grams of the excess reactant will be left over?

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Textbook Question

Urea, a substance commonly used as a fertilizer, has the for-mula CH4N2O. What is its percent composition by mass?

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Textbook Question

Calculate the mass percent composition of each of the following substances. (a) Malachite, a copper-containing mineral: Cu₂(OH)₂CO₃

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Sodium borohydride, NaBH4, a substance used in the synthesis of many pharmaceutical agents, can be prepared by reaction of NaH with B2H6 according to the equation 2 NaH + B2H6 → 2 NaBH4 (a) How many grams of NaBH4 can be prepared by reaction between 8.55 g of NaH and 6.75 g of B2H6?

Verified Solution

Key Concepts

Stoichiometry

Limiting Reactant

Molar Mass