Chemical equations water

A.queous Solubility. SolubiHty of a chemical in water can be calculated rigorously from equiHbrium thermodynamic equations. Because activity coefficient data are often not available from the Hterature or direct experiments, models such as UNIFAC can be used for stmcture—activity estimations (24). Phase-equiHbrium relationships can then be appHed to predict miscibility. Simplified calculations are possible for low miscibiHty however, when there is a high degree of miscibility, the phase-equiHbrium relationships must be solved rigorously. 

Theoretical Oxygen and Air for Combustion The amount of oxidant (oxygen or air) just sufficient to burn the carbon, hydrogen, and sulfur in a fuel to carbon dioxide, water vapor, and sulfur dioxide is the theoretical or stoichiometric oxygen or air requirement. The chemical equation for complete combustion of a fuel is... 

Write properly balanced chemical equations for the oxidation to COg and water of (a) myristic acid, (b) stearic acid, (c) a-linolenic acid, and (d) arachidonic acid. 

Plants store solar energy by photosynthesis. During photosynthesis, carbon dioxide (COj) and water (H2O) in the presence of light are converted into glucose (C(,H 20(,) by the following chemical equation ... 

As pointed out in Chapter 2, when an ionic solid dissolves in water, the cations and anions separate from each other. This process can be represented by a chemical equation in which the reactant is the solid and the products are the positive and negative ions in water (aqueous) solution. For the dissolving of MgCl2, the equation is... 

Although we have introduced net ionic equations to represent precipitation reactions, they have a much wider application. Indeed, we will use them for all kinds of reactions in water solution. In particular all of the chemical equations written throughout this chapter are net ionic equations. 

Write a chemical equation, using molecular formulas, for the reaction of sucrose with water to form glucose and fructose. 

For the reaction between solid sodium and water, the complete, balanced chemical equation is therefore... 

Now we come to an important interpretation of a chemical equation. First, we note that the equation for the reaction of sodium with water tells us that... 

Sometimes we need to construct a balanced chemical equation from the description of a reaction. For example, methane, CH4, is the principal ingredient of natural gas (Fig. H.3). It burns in oxygen to form carbon dioxide and water, both formed initially as gases. To write the balanced equation for the reaction, we first write the skeletal equation ... 

Write and balance the chemical equation for the combustion of hexane, GfcH14, to gaseous carbon dioxide gas and gaseous water. 

H.7 Write a balanced chemical equation for each of the following reactions, (a) Calcium metal reacts with water to produce hydrogen gas and aqueous calcium hydroxide. 

In a precipitation reaction, an insoluble solid product forms when we mix two electrolyte solutions. When an insoluble substance is formed in water, it immediately precipitates. In the chemical equation for a precipitation reaction, we use (aq) to indicate substances that are dissolved in water and (s) to indicate the solid that has precipitated ... 

J.ll In each of the following salts, either the cation or the anion is a weak acid or a weak base. Write the chemical equation for the proton transfer reaction of this cation or anion with water (a) NaC6H50 (b) KCIO (c) C,HSNHCI ... 

J.12 C6HsNH3C1 is a chloride salt with an acidic cation, (a) If 50.0 g of C6H5NH3C1 is dissolved in water to make 150.0 mL of solution, what is the initial molarity of the cation (b) Write the chemical equation for the proton transfer reaction of the cation with water. Identify the acid and the base in this reaction. 

J.I3 Na As04 is a salt of a weak base that can accept more than one proton, (a) Write the chemical equations for the sequential proton transfer reactions of the anion with water. Identify the acid and the base in each reaction, (b) If 35.0 g of Na3As04 is dissolved in water to make 250.0 ml. of solution, how many moles of sodium cations are in the solution ... 

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,. 

STRATEGY Begin by writing the chemical equation for the complete oxidation of octane to carbon dioxide and water. Then calculate the theoretical yield (in grams) of CO, by using the procedure in Toolbox L.l. To avoid rounding errors, do all the numerical work at the end of the calculation. To obtain the percentage yield, divide the actual I mass produced by the theoretical mass of product and multiply by 100%. 

Calcium carbide, CaC2, reacts with water to form calcium hydroxide and the flammable gas ethyne (acetylene). This reaction was once used for lamps on bicycles, because the reactants are easily transported, (a) Which is the limiting reactant when 1.00 X 102 g of water reacts with 1.00 X 102 g of calcium carbide (b) What mass of ethyne can he produced (c) What mass of excess reactant remains after reaction is complete Assume that the calcium carbide is pure and that all the ethyne produced is collected. The chemical equation is... 

The enthalpy of solution of ammonium nitrate in water is positive, (a) Does NH4N05 dissolve endothermically or exothermically (b) Write the chemical equation for the dissolving process, (c) Which is larger for NH4NO , the lattice enthalpy or the enthalpy of hydration ... 

STRATEGY Because NH4+ is a weak acid and Cl- is neutral, we expect pH < 7. We treat the solution as that of a weak acid, using an equilibrium table as in Toolbox 10.1 to calculate the composition and hence the pH. First, write the chemical equation for proton transfer to water and the expression for Ca. Obtain the value of Ka from Kh for the conjugate base by using K, = KxJKh (Eq. 11a). The initial concentration of the acidic cation is equal to the concentration of the cation that the salt would produce if the salt were fully dissociated and the cation retained all its acidic protons. The initial concentrations of its conjugate base and H30+ are assumed to be zero. 

Many of the reactions that take place in water have analogous reactions in liquid ammonia, (a) Write the chemical equation for the autoprotolysis of NH,. (b) What are the formulas of the acid and base species that result from the autoprotolysis of... 

X 10 4 M HCl(aq) with phenolphthalein indicator to see how much NaOH was left unreacted. They found that 30.2 mL of HCl(aq) was required to reach the stoichiometric point, (a) Write the balanced chemical equation for the reaction of S02 and water, (b) What amount of NaOH (in mol) had reacted with the SO, (c) What was the concentration of sulfur dioxide in the air, in parts per million ... 

Balancing the chemical equation for a redox reaction by inspection can be a real challenge, especially for one taking place in aqueous solution, when water may participate and we must include HzO and either H+ or OH. In such cases, it is easier to simplify the equation by separating it into its reduction and oxidation half-reactions, balance the half-reactions separately, and then add them together to obtain the balanced equation for the overall reaction. When adding the equations for half-reactions, we match the number of electrons released by oxidation with the number used in reduction, because electrons are neither created nor destroyed in chemical reactions. The procedure is outlined in Toolbox 12.1 and illustrated in Examples 12.1 and 12.2. 

Self-Test 14.6A Write the chemical equation for the reaction that would occur if you tried to put out a magnesium fire with water. 

Write a balanced chemical equation for (a) the hydrogenation of ethyne (acetylene, C2H2) to ethene (C2H4) by hydrogen (give the oxidation number of the carbon atoms in the reactant and product) (b) the shift reaction (sometimes called the water gas shift reaction, WGSR) (c) the reaction of barium hydride with water. 

Write the chemical equation for the reaction between magnesium metal and hot water. 

Write the chemical equation for (a) the industrial preparation of magnesium metal from the magnesium chloride in seawater (b) the action of water on calcium metal. 

Urea, (, G(NH,), reacts with water to form ammonium carbonate. Write the chemical equation and calculati the ma ol ammonium carbonate that can be obtained from 4.0 ks ot nrc... 

The common acid anhydrides of nitrogen arc O, 1 , and N,0,. Write the formulas of their corresponding acids ind chemical equations for the formation of the acids by the reaction of the anhydrides with water. 

Write the balanced chemical equation for (a) the thermal decomposition of potassium chlorate without a catalyst (b) the reaction of bromine with water (c) the reaction between sodium chloride and concentrated sulfuric acid, (d) Identify each reaction as a Bronsted acid—base, Lewis acid—base, or redox reaction. 

Write the balanced chemical equation for the reaction of chlorine with water in (a) a neutral aqueous solution (b) a dilute basic solution (c) a concentrated basic solution. 

It is easiest to balance a chemical equation one element at a time, starting with the elements that appear in only one substance on each side. Notice that all of the carbon atoms in propane end up in carbon dioxide molecules, and all of propane s hydrogen atoms appear in water molecules. This feature allows us to balance carbon and hydrogen easily. 

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 sulfur dioxide reacts with more hydrogen sulfide to give elemental sulfur and water. Write balanced chemical equations for these two reactions, and determine the minimum mass of hydrogen sulfide that a volcano must emit in order to deposit 1.25 kg of sulfiir. 

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