## Writing an Equation for the Reaction

Sean Hormozian 2D
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Joined: Fri Sep 26, 2014 2:02 pm

### Writing an Equation for the Reaction

In the fundamentals section in the book, on page F103, Number M.3 says, "Sold boron can be extracted from solid boron oxide by reaction with magnesium metal at a high temperature. A second product is solid magnesium oxide. Write a balanced equation for the reaction".

- I understand how to balance the equation, but I don't understand how to write the original equation with its various subscripts. For example, why is solid boron oxide B2O3?

Chem_Mod
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### Re: Writing an Equation for the Reaction

Since we have not done enough inorganic chemistry the name and formula would be given.

O has a common oxidation state of -2.
B in group 3 has a common oxidation state of +3.

-2 x 3 = -6
+3 x 2 = +6

Therefore B2O3 gives a net charge = 0

Sean Hormozian 2D
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Joined: Fri Sep 26, 2014 2:02 pm

### Re: Writing an Equation for the Reaction

how would you figure out the oxidation state?

Justin Le 2I
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### Re: Writing an Equation for the Reaction

You can figure out the oxidation state by looking at your periodic table and noting the groups that boron and oxygen are in. Boron is in group 13, which typically has an oxidation state of +3. Aluminum is also +3. Oxygen is in group 16, or 2 groups from the end so it's oxidation state is -2.

504655187
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### Re: Writing an Equation for the Reaction

what do you include in a chemical reaction equation when the question includes the combustion of a molecule?

rebeccawaggoner 1H
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### Re: Writing an Equation for the Reaction

When an element or molecule combusts, you must add O2 gas.

Henna Dialani 4I
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### Re: Writing an Equation for the Reaction

504655187 wrote:what do you include in a chemical reaction equation when the question includes the combustion of a molecule?

O2 is needed for a combustion reaction as the word combustion implies 'burning in the presence of oxygen'.

Maggie Eberhardt - 2H
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### Re: Writing an Equation for the Reaction

I was wondering if anyone could help me solve this one, I honestly have no idea where to start.

(Just to repeat it)
M.7 Solid boron can be extracted from solid boron oxide by reaction with magnesium metal at a high temperature. A second product is solid magnesium oxide. (a) Write a balanced equation for the reaction. (b) What mass of boron can be produced when 125 kg of boron oxide is heated with 125 kg of magnesium?

Ethan Lam 4A
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Joined: Thu Jul 11, 2019 12:17 am

### Re: Writing an Equation for the Reaction

For part a, I got B203 + 3Mg -> 3Mg0 +2B due to Law of Conservation of Mass. For part b, you need to convert the 125 grams of both reactants into the amount of Boron by using the molar mass and the mole ratio from the balanced equation to see which reactant produces less product.

Eva Zhao 4I
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Joined: Sun Sep 29, 2019 12:16 am

### Re: Writing an Equation for the Reaction

Just to add onto the topic of combustion, O2 (oxygen gas) is reacted with the given fuel for the products of CO2 (carbon dioxide) and H2O (water). Depending on the fuel, you may need to balance the equation.