Balanced chemical equation, mole

Chemical Formulas Balancing Chemical Equations Mole Ratios... 

To solve the problem, you need to know how the unknown moles of hydrogen are related to the known moles of potassium. In Section 11.1, you learned to derive mole ratios from the balanced chemical equation. Mole ratios are used as conversion factors to convert the known number of moles of one substance to the unknown number of moles of another substance in the same reaction. Several mole ratios can be written from the equation, but how do you choose the correct one ... 

Why learn to write mole ratios They are the key to calculations that are based on chemical equations. Using a balanced chemical equation, mole ratios derived from the equation, and a given amount of one of the reactants or products, you can calculate the amount of any other participant in the reaction. 

In taking these sums, the standard molar entropies are multiplied by the number of moles specified in the balanced chemical equation. 

More quantitative evidence can be obtained by carrying out the reaction between an excess of sodium and a weighed amount of ethanol and measuring the amount of hydrogen gas evolved. When this is done it is found that 46 grams of ethanol (one mole) will produce only mole of hydrogen gas. We can therefore write a balanced chemical equation for the reaction of sodium with ethanol ... 

In other words, the stoichiometric coefficients multiplying the chemical formulas in any balanced chemical equation tell us the relative number of moles of each substance that reacts or is produced in the reaction. 

A balanced chemical equation symbolizes both the qualitative and the quantitative changes that take place in a chemical reaction. The stoichiometric coefficients tell us the relative numbers of moles of reactants and products taking part in the reaction. 

J.I4 The oxides of nonmetallic elements are called acidic oxides because they form acidic solutions in water. Write the balanced chemical equations for the reaction of one mole of each acidic oxide with one mole of water molecules to form an oxoacid and name the acid formed (a) C02 (b) SO,. 

Sometimes we need to know how much product to expect from a reaction, or how much reactant we need to make a desired amount of product. The quantitative aspect of chemical reactions is the part of chemistry called reaction stoichiometry. The key to reaction stoichiometry is the balanced chemical equation. Recall from Section H that a stoichiometric coefficient in a chemical equation tells us the relative amount (number of moles) of a substance that reacts or is produced. Thus, the stoichiometric coefficients in... 

The balanced chemical equation for a reaction is used to set up the mole ratio, a factor that is used to convert the amount of one substance into the amount of another. 

Step 2 Use the mole ratio derived from the stoichiometric coefficients in the balanced chemical equation to convert from the amount of one substance (A) into the amount in moles of the other substance (B). For aA - / B or aA + hY> — cC, use... 

The confusion was probably caused by the different stoichiometries of the balanced chemical equations, with one mole of sodium hydroxide reacting with one mole of dilute hydrochloric acid but two moles of the alkali reacting with one mole of dilute sulphuric acid. 

Sections 2- and 3- describe how to use the relationships among atoms, moles, and masses to answer how much questions about individual substances. Combining these ideas with the concept of a balanced chemical equation lets us answer how much questions about chemical reactions. The study of the amounts of materials consumed and produced in chemical reactions is called stoichiometry. 

To summarize, the amounts of different reagents that participate in a chemical reaction are related through the stoichiometric coefficients in the balanced chemical equation. To convert from moles of one reagent to moles of any other reagent, multiply by the stoichiometric ratio that leads to proper cancellation of units ... 

Tables of amounts are useful in stoichiometry calculations for precipitation reactions. For example, a precipitate of Fe (OH) forms when 50.0 mL of 1.50 M NaOH is mixed with 35.0 mL of 1.00 M FeCl3 solution. We need a balanced chemical equation and amounts in moles to calculate how much precipitate forms. The balanced chemical equation is the net reaction for formation of Fe (OH)3 Fe (ag) + 3 OH (a g) Fe (OH)3 (. )...

Solid magnesium has been transformed into Mg ions, and hydronium ions have decomposed to give H2 gas and water molecules. Quantitative measurements reveal that for every mole of Mg consumed, the reaction also consumes two moles of H3O+, and it produces one mole of H2 and two moles of water. The reaction can be summed up in the following balanced chemical equation Mg(,S ) + 2 q) Mg (i2 q) + H2(g) + 2 Hz 0(1)... 

The balanced chemical equation for combustion applies to two moles of octane ... 

C06-0057. Acetylene (C2 H2) Is used In welding torches because it has a high heat of combustion. When 1.00 g of acetylene bums completely in excess O2 gas at constant volume, it releases 48.2 kJ of energy, (a) What Is the balanced chemical equation for this reaction (b) What is the molar energy of combustion of acetylene (c) How much energy is released per mole of O2 consumed ... 

The coefficients of any balanced redox equation describe the stoichiometric ratios between chemical species, just as for other balanced chemical equations. Additionally, in redox reactions we can relate moles of chemical change to moles of electrons. Because electrons always cancel in a balanced redox equation, however, we need to look at half-reactions to determine the stoichiometric coefficients for the electrons. A balanced half-reaction provides the stoichiometric coefficients needed to compute the number of moles of electrons transferred for every mole of reagent. 

When two substances react, they react in exact amounts. You can determine what amounts of the two reactants are needed to react completely with each other by means of mole ratios based on the balanced chemical equation for the reaction. In the laboratory, precise amounts of the reactants are rarely used in a reaction. Usually, there is an excess of one of the reactants. As soon as the other reactant is used up, the reaction stops. The reactant that is used up is called the limiting reactant. Based on the quantities of each reactant and the balanced chemical equation, you can predict which substance in a reaction is the limiting reactant. 

Mole ratios can be used to determine the amount of one substance needed to react with a given amount of another substance. In this experiment, you will react a substance called an acid with another substance called a base. Acids can be defined as substances that dissociate and produce hydrogen (H+) ions when dissolved in water. Bases are substances that ionize to produce hydroxide (OH ) ions when they dissolve in water. When acids and bases react with each other, the H+ ions and OH ions join to form water (H20). The resulting solution no longer has an excess of either H+ ions or OH- ions. The solution has become neutral. This process is called neutralization. By using the mole ratio of hydrogen ions and hydroxide ions in the balanced chemical equation, you can predict the point at which a solution becomes neutral. 

The balanced chemical equation may also be used to express the ratios of moles of reactants and products involved. Thus, for the reaction whose equation is given above, 1 mol of N, reacts with 3 mol of H 2 to produce 2 mol of NH,. It is also true that 4 mol of nitrogen can react with 12 mol of hydrogen to produce 8 mol of ammonia, and so on. 

Fig. 8-1 The conversion of moles of one reagent to moles of another, using a ratio of the coefficients of the balanced chemical equation as a factor label...

The balanced equation expresses quantities in moles, but it is seldom possible to measure out quantities in moles directly. If the quantities given or required are expressed in other units, it is necessary to convert them to moles before using the factors of the balanced chemical equation. Conversion of mass to moles and vice versa was considered in Sec. 4.5. Here we will use that knowledge first to calculate the number of moles of reactant or product, and then use that value to calculate the number of moles of other reactant or product. 

EXAMPLE 8.8. How many moles of NaCI can be produced by the reaction of 2.0 mol NaOH and 3.0 mol HC1 First, write the balanced chemical equation ... 

Arts. The chemist can put in as little as is weighable or as much as the vessel will hold. For example, the fact that a reactant has a coefficient of 2 in the balanced chemical equation does not mean that the chemist must put two moles into the reaction vessel. The chemist might decide to add the reactants in the ratio of the balanced chemical equation, but even that is not required. And even in that case, the numbers of moles of each reactant might be twice the respective coefficients or one-tenth those values, etc. The equation merely states the reacting ratio. 

Ans. Section 2.4, factor-label method Sec. 4.4, calculation of formula weights Sec. 4.5. changing moles to grams and vice versa Sec. 4.5, Avogadro s number and/or Sec. 7.2, balancing chemical equations. 

Sulfurous acid reacts with sodium hydroxide to produce sodium sulfite and water, (a) Write a balanced chemical equation for the reaction. (b) Determine the number of moles of sulfurous acid in 50.0g sulfurous acid, (c) How many moles of sodium sulfite will be produced by the reaction of this number of moles of sulfurous acid (d) How many grams of sodium sulfite will be produced (e) How many moles of sodium hydroxide will it take to react with this quantity of sulfurous acid (/) How many grams of sodium hydroxide will be used up ... 

In a certain experiment, lOOg of ethane, C2H, is burned, (a) Write a balanced chemical equation for the combustion of ethane to produce C02 and water. (6) Determine the number of moles of ethane in lOOg of ethane, (c) Determine the number of moles of C02 that would be produced by the combustion of that number of moles of ethane. (d) Determine the mass of C02 that can be produced by the combustion of lOOg of ethane. 

Change the moles of NH, to moles of (NH4),P04 with the balanced chemical equation. 

Find the number of moles of CO, needed to react with the number of moles of Ca(OH) present, using the balanced chemical equation. 

The net ionic equation, like all balanced chemical equations, gives the ratio of moles of each substance to moles of each of the others. It does not immediately yield information about the mass of the entire salt, however. (One cannot weigh out only Ba2+ ions.) Therefore, when masses of reactants are required, the specific compound used must be included in the calculation. The use of net ionic equations in stoichiometric calculations will be more important after study of molarity (Chap. 10). 

The balanced chemical equation shows that the ratio of moles of HC1 to Ba(OH)2 is 2 1. 

The number of moles of KCIO, may be calculated from the number of moles of O, by means of the balanced chemical equation, and that value is then converted to mass. 

Despite the fact that we start with iron(III), it only takes 1 mol e for each mole of Fe1 as shown by the balanced chemical equation. We are not reducing the iron to elementary iron. 

The changes brought about by the chemical reaction arc a little different in this case. Twice as many moles per liter of A are used up as moles per liter of C are produced. Note that the magnitudes in the middle row of this table and the coefficients in the balanced chemical equation are in the same ratio. 

The balanced chemical equation provides the factor needed to convert from moles KC103 to moles 02. Amount 02 = 1.76 mol KC103 x kCIO = m° ... 

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