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Use this medication as directed on the label, or as your doctor has prescribed. Do not use the medication in larger amounts or for longer than recommended.

You should not use this medication if you are allergic to Senokot S, or if you are also taking mineral oil.

Ask a doctor or pharmacist before using Senokot S if you own nausea, vomiting, stomach pain, a sudden change in bowel habits, or an intestinal disorder (such as Crohn’s disease or ulcerative colitis).

Do not use this medication without your doctor’s advice if you are pregnant or breast-feeding.

Do not take this medication for longer than 7 days in a row.

Call your doctor if your constipation does not improve or if it gets worse.

Stop taking this Senokot S and call your doctor at once if you own rectal bleeding, severe stomach pain, nausea and vomiting, or if you do not own a bowel movement.

Do not use any other over-the-counter laxatives or other stool softener without first asking your doctor or pharmacist.


What is Senokot S?

Docusate is a stool softener. It makes bowel movements softer and easier to pass.

Senna is a laxative.

It stimulates muscle movement in the intestines.

The combination of docusate and senna is used to treat occasional constipation.

Senokot S may also be used for other purposes not listed in this medication guide.


What happens if I overdose?

Seek emergency medical attention if you ponder you own used too much of Senokot S.

Overdose symptoms may include nausea, vomiting, stomach pain, or diarrhea.


What happens if I miss a dose?

Since Senokot S is taken as needed, you are not likely to be on a dosing schedule.

If you are taking the medication regularly, take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take additional medicine to make up the missed dose.



Hess’s law allows us to construct new chemical reactions and predict what their enthalpies of reaction will be. This is a extremely useful tool because now we don’t own to measure the enthalpy changes of every possible reaction. We need measure only the enthalpy changes of certain benchmark reactions and then use these reactions to algebraically construct any possible reaction and combine the enthalpies of the benchmark reactions accordingly.

But what are the benchmark reactions?

We need to own some agreed-on sets of reactions that provide the central data for any thermochemical equation.

Formation reactions are chemical reactions that form one mole of a substance from its constituent elements in their standard states. By standard states we mean as a diatomic molecule if that is how the element exists and the proper phase at normal temperatures (typically room temperature). The product is one mole of substance, which may require that coefficients on the reactant side be fractional (a change from our normal insistence that every coefficients be whole numbers). For example, the formation reaction for methane (CH4) is

C(s) + 2 H2(g) → CH4(g)

The formation reaction for carbon dioxide (CO2) is

C(s) + O2(g) → CO2(g)

In both cases, one of the elements is a diatomic molecule because that is the standard state for that specific element.

The formation reaction for H2O—

2 H2(g) + O2(g) → 2 H2O(ℓ)

—is not in a standard state because the coefficient on the product is 2; for a proper formation reaction, only one mole of product is formed. Thus, we own to divide every coefficients by 2:

H2(g) + 1/2 O2(g) → H2O(ℓ)

On a molecular scale, we are using half of an oxygen molecule, which may be problematic to visualize. However, on a molar level, it implies that we are reacting only half of a mole of oxygen molecules, which should be an simple concept for us to understand.

Key Takeaways

  1. In this reaction, two moles of product are produced, so this is not a proper formation reaction.
  2. Define formation reaction and give an example.

  3. Fe(s) + 1/2 O2(g) → FeO(s)
  4. In this reaction, one mole of a substance is produced from its elements in their standard states, so this is a proper formation reaction.
  5. CaO(s) + CO2 → CaCO3(s)
  6. H2(g) + Cl2(g) → 2 HCl(g)
  7. Which of the following reactions is a formation reaction?

    If it is not a formation reaction, explain why.

  8. C2H6(g)
  9. Explain the importance of formation reactions in thermochemical equations.

  10. FeO(s)
  11. One mole of a substance is produced, but it is produced from two other compounds, not its elements. So this is not a proper formation reaction.
  12. A formation reaction is the formation of one mole of a substance from its constituent elements.
  13. Define a formation reaction and be capable to recognize one.
  14. Si(s) + 2 F2(g) → SiF4(g)
  15. Enthalpies of formation are used to determine the enthalpy change of any given reaction.
  16. 2 C(s) + 3 H2(g) → C2H6(g)
  17. Use enthalpies of formation to determine the enthalpy of reaction.

Example 13

Show that the reaction

Fe2O3(s) + 3 SO3(g) → Fe2(SO4)3(s)

can be written as a combination of formation reactions.

Solution

There will be three formation reactions.

The one for the products will be written as a formation reaction, while the ones for the reactants will be written in reverse. Furthermore, the formation reaction for SO3 will be multiplied by 3 because there are three moles of SO3 in the balanced chemical equation. The formation reactions are as follows:

2 Fe(s) + 3 S(s) + 6 O2(g) → Fe2(SO4)3(s)

When these three equations are combined and simplified, the overall reaction is

Fe2O3(s) + 3 SO3(s) → Fe2(SO4)3(s)

Test Yourself

Write the formation reactions that will yield

2 SO2(g) + O2(g) → 2 SO3(g).

Answer

Now that we own established formation reactions as the major type of thermochemical reaction we will be interested in, do we always need to record every the formation reactions when we desire to determine the enthalpy change of any random chemical reaction?

No. There is an easier way. You may own noticed in every our examples that we change the signs on every the enthalpies of formation of the reactants, and we don’t change the signs on the enthalpies of formation of the products. We also multiply the enthalpies of formation of any substance by its coefficient—technically, even when it is just 1.

What is a class 3 allergy

This allows us to make the following statement: the enthalpy change of any chemical reaction is equal to the sum of the enthalpies of formation of the products minus the sum of the enthalpies of formation of the reactants. In mathematical terms,

where np and nr are the number of moles of products and reactants, respectively (even if they are just 1 mol), and ΔHf,p and ΔHf,r are the enthalpies of formation of the product and reactant species, respectively. This products-minus-reactants scheme is extremely useful in determining the enthalpy change of any chemical reaction, if the enthalpy of formation data are available.

Because the mol units cancel when multiplying the quantity by the enthalpy of formation, the enthalpy change of the chemical reaction has units of energy (joules or kilojoules) only.

Example 12

Write formation reactions for each of the following.

  • FeO(s)
  • C2H6(g)

Solution

In both cases, there is one mole of the substance as product, and the coefficients of the reactants may own to be fractional to balance the reaction.

Solution

In both cases, there is one mole of the substance as product, and the coefficients of the reactants may own to be fractional to balance the reaction.

  • Fe(s) + 1/2 O2(g) → FeO(s)
  • 2 C(s) + 3 H2(g) → C2H6(g)

Test Yourself

Write the equation for the formation of CaCO3(s).

Answer

Ca(s) + C(s) + 3/2 O2(g) → CaCO3(s)

The enthalpy change for a formation reaction is called the enthalpy of formation The subscript f is the clue that the reaction of interest is a formation reaction.

Thus, for the formation of FeO(s),

Note that now we are using kJ/mol as the unit because it is understood that the enthalpy change is for one mole of substance. Note, too, by definition, that the enthalpy of formation of an element is exactly zero because making an element from an element is no change. For example,

H2(g) → H2(g) ΔHf = 0

Formation reactions and their enthalpies are significant because these are the thermochemical data that are tabulated for any chemical reaction.

Table Enthalpies of Formation for Various Substances lists some enthalpies of formation for a variety of substances; in some cases, however, phases can be significant (e.g., for H2O).

It is simple to show that any general chemical equation can be written in terms of the formation reactions of its reactants and products, some of them reversed (which means the sign must change in accordance with Hess’s law). For example, consider

2 NO2(g) → N2O4(g)

We can record it in terms of the (reverse) formation reaction of NO2 and the formation reaction of N2O4:

We must multiply the first reaction by 2 to get the correct overall balanced equation.

We are simply using Hess’s law in combining the ΔHf values of the formation reactions.

Table Enthalpies of Formation for Various Substances

Compound ΔHf (kJ/mol) Compound ΔHf (kJ/mol) Compound ΔHf (kJ/mol) Compound ΔHf (kJ/mol)
Ag(s) 0 Ca(s) 0 Hg2Cl2(s) NaHCO3(s)
AgBr(s) CaCl2(s) I2(s) 0 NaN3(s)
AgCl(s) CaCO3(s, arag) −1, K(s) 0 Na2CO3(s) −1,
Al(s) 0 CaCO3(s, calc) −1, KBr(s) Na2O(s)
Al2O3(s) −1, Cl2(g) 0 KCl(s) Na2SO4(s)
Ar(g) 0 Cr(s) 0 KF(s) Ne(g) 0
Au(s) 0 Cr2O3(s) −1, KI(s) Ni(s) 0
BaSO4(s) −1, Cs(s) 0 Li(s) 0 O2(g) 0
Br2(ℓ) 0 Cu(s) 0 LiBr(s) O3(g)
C(s, dia) F2(g) 0 LiCl(s) PH3(g)
C(s, gra) 0 Fe(s) 0 LiF(s) Pb(s) 0
CCl4(ℓ) Fe2(SO4)3(s) −2, LiI(s) PbCl2(s)
CH2O(g) Fe2O3(s) Mg(s) 0 PbO2(s)
CH3COOH(ℓ) Ga(s) 0 MgO(s) PbSO4(s)
CH3OH(ℓ) HBr(g) NH3(g) Pt(s) 0
CH4(g) HCl(g) NO(g) S(s) 0
CO(g) HF(g) NO2(g) SO2(g)
CO2(g) HI(g) N2(g) 0 SO3(g)
C2H5OH(ℓ) HNO2(g) N2O(g) SO3(ℓ)
C2H6(g) HNO3(g) N2O4(g) Si(s) 0
C6H12(ℓ) H2(g) 0 N2O5(g) U(s) 0
C6H12O6(s) H2O(g) Na(s) 0 UF6(s) −2,
C6H14(ℓ) H2O(ℓ) NaBr(s) UO2(s) −1,
C6H5CH3(ℓ) H2O(s) NaCl(s) Xe(g) 0
C6H6(ℓ) He(g) 0 NaF(s) Zn(s) 0
C10H8(s) Hg(ℓ) 0 NaI(s) ZnCl2(s)
C12H22O11(s) −2,

Sources: National Institute of Standards and Technology’s Chemistry WebBook, ; D.

R. Lide, ed., CRC Handbook of Chemistry and Physics, 89th ed. (Boca Raton, FL: CRC Press, ); J.

What is a class 3 allergy

A. Dean, ed., Lange’s Handbook of Chemistry, 14th ed. (New York: McGraw-Hill, ).

Exercises

Test Yourself

Write the equation for the formation of CaCO3(s).

Answer

Ca(s) + C(s) + 3/2 O2(g) → CaCO3(s)

The enthalpy change for a formation reaction is called the enthalpy of formation The subscript f is the clue that the reaction of interest is a formation reaction. Thus, for the formation of FeO(s),

Note that now we are using kJ/mol as the unit because it is understood that the enthalpy change is for one mole of substance. Note, too, by definition, that the enthalpy of formation of an element is exactly zero because making an element from an element is no change.

For example,

H2(g) → H2(g) ΔHf = 0

Formation reactions and their enthalpies are significant because these are the thermochemical data that are tabulated for any chemical reaction. Table Enthalpies of Formation for Various Substances lists some enthalpies of formation for a variety of substances; in some cases, however, phases can be significant (e.g., for H2O).

It is simple to show that any general chemical equation can be written in terms of the formation reactions of its reactants and products, some of them reversed (which means the sign must change in accordance with Hess’s law).

For example, consider

2 NO2(g) → N2O4(g)

We can record it in terms of the (reverse) formation reaction of NO2 and the formation reaction of N2O4:

We must multiply the first reaction by 2 to get the correct overall balanced equation. We are simply using Hess’s law in combining the ΔHf values of the formation reactions.

Table Enthalpies of Formation for Various Substances

Compound ΔHf (kJ/mol) Compound ΔHf (kJ/mol) Compound ΔHf (kJ/mol) Compound ΔHf (kJ/mol)
Ag(s) 0 Ca(s) 0 Hg2Cl2(s) NaHCO3(s)
AgBr(s) CaCl2(s) I2(s) 0 NaN3(s)
AgCl(s) CaCO3(s, arag) −1, K(s) 0 Na2CO3(s) −1,
Al(s) 0 CaCO3(s, calc) −1, KBr(s) Na2O(s)
Al2O3(s) −1, Cl2(g) 0 KCl(s) Na2SO4(s)
Ar(g) 0 Cr(s) 0 KF(s) Ne(g) 0
Au(s) 0 Cr2O3(s) −1, KI(s) Ni(s) 0
BaSO4(s) −1, Cs(s) 0 Li(s) 0 O2(g) 0
Br2(ℓ) 0 Cu(s) 0 LiBr(s) O3(g)
C(s, dia) F2(g) 0 LiCl(s) PH3(g)
C(s, gra) 0 Fe(s) 0 LiF(s) Pb(s) 0
CCl4(ℓ) Fe2(SO4)3(s) −2, LiI(s) PbCl2(s)
CH2O(g) Fe2O3(s) Mg(s) 0 PbO2(s)
CH3COOH(ℓ) Ga(s) 0 MgO(s) PbSO4(s)
CH3OH(ℓ) HBr(g) NH3(g) Pt(s) 0
CH4(g) HCl(g) NO(g) S(s) 0
CO(g) HF(g) NO2(g) SO2(g)
CO2(g) HI(g) N2(g) 0 SO3(g)
C2H5OH(ℓ) HNO2(g) N2O(g) SO3(ℓ)
C2H6(g) HNO3(g) N2O4(g) Si(s) 0
C6H12(ℓ) H2(g) 0 N2O5(g) U(s) 0
C6H12O6(s) H2O(g) Na(s) 0 UF6(s) −2,
C6H14(ℓ) H2O(ℓ) NaBr(s) UO2(s) −1,
C6H5CH3(ℓ) H2O(s) NaCl(s) Xe(g) 0
C6H6(ℓ) He(g) 0 NaF(s) Zn(s) 0
C10H8(s) Hg(ℓ) 0 NaI(s) ZnCl2(s)
C12H22O11(s) −2,

Sources: National Institute of Standards and Technology’s Chemistry WebBook, ; D.

R. Lide, ed., CRC Handbook of Chemistry and Physics, 89th ed. (Boca Raton, FL: CRC Press, ); J. A. Dean, ed., Lange’s Handbook of Chemistry, 14th ed. (New York: McGraw-Hill, ).

Exercises

  • Explain the importance of formation reactions in thermochemical equations.

  • Define formation reaction and give an example.

  • Which of the following reactions is a formation reaction? If it is not a formation reaction, explain why.

a)  H2(g) + S(s) → H2S(g)

b)  2 HBr(g) + Cl2(g) → 2 HCl(g) + Br2(ℓ)

4.

Which of the following reactions is a formation reaction? If it is not a formation reaction, explain why.

a)  Fe(g) + 1/2 O2(g) → FeO(s)

b)  Hg(ℓ) + 1/2 O2(g) → HgO(s)

5. Which of the following reactions is a formation reaction? If it is not a formation reaction, explain why.

a)  H2(g) + S(s) + 2 O2(g) → H2SO4(ℓ)

b)  C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(ℓ)

6.

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Which of the following reactions is a formation reaction? If it is not a formation reaction, explain why.

a)  Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g)

b)  2 Na(s) + C(s) + 3/2 O2(g) → Na2CO3(s)

7. Record a proper formation reaction for each substance.

a)  H3PO4(s)

b)  Na2O(s)

c)  C3H7OH(ℓ)

8. Record a proper formation reaction for each substance.

a)  N2O5(g)

b)  BaSO4(s)

c)  Fe(OH)3(s)

9.

Record a proper formation reaction for each substance.

a)  C12H22O11(s)

b)  Zn(NO3)2(s)

c)  Al(OH)3(s)

 Write a proper formation reaction for each substance.

a)  O3(g)

b)  Na2O2(s)

c)  PCl5(g)

 Write this reaction in terms of formation reactions.

MgCO3(s) → MgO(s) + CO2(g)

 Write this reaction in terms of formation reactions.

2 NO + 4 NO2 → 2 N2O5 + N2

Record this reaction in terms of formation reactions.

2 CuCl(s) → Cu(s) + CuCl2(s)

 Write this reaction in terms of formation reactions.

SiH4 + 4 F2 → SiF4 + 4 HF

Answers

1.

A formation reaction is a reaction that produces one mole of a substance from its elements.

Example: C(s) + O2(g) → CO2(g)

3.

a)  formation reaction

b)  It is not the formation of a single substance, so it is not a formation reaction.

5.

a)  formation reaction

b)  It is not the formation of a single substance, so it is not a formation reaction.

7.

a)  3/2 H2(g) + P(s) + 2 O2(g) → H3PO4(s)

b)  2 Na(s) + 1/2 O2(g) → Na2O(s)

c)  3 C(s) + 1/2 O2(g) + 4 H2(g) → C3H7OH(ℓ)

9.

a)  12 C(s) + 11 H2(g) + 11/2 O2(g) → C12H22O11(s)

b)  Zn(s) + N2(g) + 3 O2(g) → Zn(NO3)2

c)  Al(s) + 3/2 O2(g) + 3/2 H2(g) → Al(OH)3(s)

a)  MgCO3(s) → Mg(s) + C(s) + 3/2 O2(g)

b)  Mg(s) + 1/2 O2(g) → MgO(s)

c)  C(s) + O2(g) → CO2(g)

a)  2 × [CuCl(s) → Cu(s) + 1/2 Cl2(g)]

b)  Cu(s) → Cu(s)

c)  Cu(s) + Cl2(g) → CuCl2(s)

ΔH = − kJ

ΔH = − kJ

Food and Drink App: Calories and Nutrition

Section Energy mentioned the connection between the calorie unit and nutrition: the calorie is the common unit of energy used in nutrition, but we really consider the kilocalorie (spelled Calorie with a capital C).

A daily diet of 2, Cal is actually 2,, cal, or over 8,, J, of energy.

Nutritionists typically generalize the Calorie content of foods by separating it into the three main food types: proteins, carbohydrates, and fats. The general law of thumb is as follows:

If the food is It has this energy content
protein 4 Cal/g
carbohydrate 4 Cal/g
fat 9 Cal/g

This table is extremely useful. Assuming a 2, Cal daily diet, if our diet consists solely of proteins and carbohydrates, we need only about g of food for sustenance—a little more than a pound.

If our diet consists solely of fats, we need only about g of food—less than a half pound. Of course, most of us own a mixture of proteins, carbohydrates, and fats in our diets. Water has no caloric worth in the diet, so any water in the diet is calorically useless. (However, it is significant for hydration; also, numerous forms of water in our diet are highly flavoured and sweetened, which bring other nutritional issues to bear.)

When your body works, it uses calories provided by the diet as its energy source. If we eat more calories than our body uses, we acquire weight—about 1 lb of weight for every additional 3, Cal we ingest.

Similarly, if we desire to lose weight, we need to expend an additional 3, Cal than we ingest to lose 1 lb of weight. No fancy or fad diets are needed; maintaining an ideal body weight is a straightforward matter of thermochemistry—pure and simple.

Example 14

Use the products-minus-reactants approach to determine the enthalpy of reaction for

Solution

The enthalpies of formation are multiplied by the number of moles of each substance in the chemical equation, and the entire enthalpy of formation for reactants is subtracted from the entire enthalpy of formation of the products:

ΔHrxn=[(2 mol)(− kJ/ mol)+(1 mol)(0 kJ/ mol)]−[(2 mol)(− kJ/ mol)+(1 mol)(0 kJ/ mol)]

All the mol units cancel.

Multiplying and combining every the values, we get

ΔHrxn = − kJ

Test Yourself

What is the enthalpy of reaction for this chemical equation?

Answer

+ kJ

Example 11

Which of the following are proper formation reactions?

a)  H2(g) + S(s) → H2S(g)

b)  2 HBr(g) + Cl2(g) → 2 HCl(g) + Br2(ℓ)

4. Which of the following reactions is a formation reaction? If it is not a formation reaction, explain why.

a)  Fe(g) + 1/2 O2(g) → FeO(s)

b)  Hg(ℓ) + 1/2 O2(g) → HgO(s)

5.

Which of the following reactions is a formation reaction? If it is not a formation reaction, explain why.

a)  H2(g) + S(s) + 2 O2(g) → H2SO4(ℓ)

b)  C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(ℓ)

6. Which of the following reactions is a formation reaction? If it is not a formation reaction, explain why.

a)  Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g)

b)  2 Na(s) + C(s) + 3/2 O2(g) → Na2CO3(s)

7.

Record a proper formation reaction for each substance.

a)  H3PO4(s)

b)  Na2O(s)

c)  C3H7OH(ℓ)

8.

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Record a proper formation reaction for each substance.

a)  N2O5(g)

b)  BaSO4(s)

c)  Fe(OH)3(s)

9. Record a proper formation reaction for each substance.

a)  C12H22O11(s)

b)  Zn(NO3)2(s)

c)  Al(OH)3(s)

 Write a proper formation reaction for each substance.

a)  O3(g)

b)  Na2O2(s)

c)  PCl5(g)

 Write this reaction in terms of formation reactions.

MgCO3(s) → MgO(s) + CO2(g)

 Write this reaction in terms of formation reactions.

2 NO + 4 NO2 → 2 N2O5 + N2

Record this reaction in terms of formation reactions.

2 CuCl(s) → Cu(s) + CuCl2(s)

 Write this reaction in terms of formation reactions.

SiH4 + 4 F2 → SiF4 + 4 HF

Answers

1.

A formation reaction is a reaction that produces one mole of a substance from its elements.

Example: C(s) + O2(g) → CO2(g)

3.

a)  formation reaction

b)  It is not the formation of a single substance, so it is not a formation reaction.

5.

a)  formation reaction

b)  It is not the formation of a single substance, so it is not a formation reaction.

7.

a)  3/2 H2(g) + P(s) + 2 O2(g) → H3PO4(s)

b)  2 Na(s) + 1/2 O2(g) → Na2O(s)

c)  3 C(s) + 1/2 O2(g) + 4 H2(g) → C3H7OH(ℓ)

9.

a)  12 C(s) + 11 H2(g) + 11/2 O2(g) → C12H22O11(s)

b)  Zn(s) + N2(g) + 3 O2(g) → Zn(NO3)2

c)  Al(s) + 3/2 O2(g) + 3/2 H2(g) → Al(OH)3(s)

a)  MgCO3(s) → Mg(s) + C(s) + 3/2 O2(g)

b)  Mg(s) + 1/2 O2(g) → MgO(s)

c)  C(s) + O2(g) → CO2(g)

a)  2 × [CuCl(s) → Cu(s) + 1/2 Cl2(g)]

b)  Cu(s) → Cu(s)

c)  Cu(s) + Cl2(g) → CuCl2(s)

ΔH = − kJ

ΔH = − kJ

Food and Drink App: Calories and Nutrition

Section Energy mentioned the connection between the calorie unit and nutrition: the calorie is the common unit of energy used in nutrition, but we really consider the kilocalorie (spelled Calorie with a capital C).

A daily diet of 2, Cal is actually 2,, cal, or over 8,, J, of energy.

Nutritionists typically generalize the Calorie content of foods by separating it into the three main food types: proteins, carbohydrates, and fats.

What is a class 3 allergy

The general law of thumb is as follows:

If the food is It has this energy content
protein 4 Cal/g
carbohydrate 4 Cal/g
fat 9 Cal/g

This table is extremely useful. Assuming a 2, Cal daily diet, if our diet consists solely of proteins and carbohydrates, we need only about g of food for sustenance—a little more than a pound.

If our diet consists solely of fats, we need only about g of food—less than a half pound. Of course, most of us own a mixture of proteins, carbohydrates, and fats in our diets. Water has no caloric worth in the diet, so any water in the diet is calorically useless. (However, it is significant for hydration; also, numerous forms of water in our diet are highly flavoured and sweetened, which bring other nutritional issues to bear.)

When your body works, it uses calories provided by the diet as its energy source.

What is a class 3 allergy

If we eat more calories than our body uses, we acquire weight—about 1 lb of weight for every additional 3, Cal we ingest. Similarly, if we desire to lose weight, we need to expend an additional 3, Cal than we ingest to lose 1 lb of weight. No fancy or fad diets are needed; maintaining an ideal body weight is a straightforward matter of thermochemistry—pure and simple.

Example 14

Use the products-minus-reactants approach to determine the enthalpy of reaction for

Solution

The enthalpies of formation are multiplied by the number of moles of each substance in the chemical equation, and the entire enthalpy of formation for reactants is subtracted from the entire enthalpy of formation of the products:

ΔHrxn=[(2 mol)(− kJ/ mol)+(1 mol)(0 kJ/ mol)]−[(2 mol)(− kJ/ mol)+(1 mol)(0 kJ/ mol)]

All the mol units cancel.

What is a class 3 allergy

Multiplying and combining every the values, we get

ΔHrxn = − kJ

Test Yourself

What is the enthalpy of reaction for this chemical equation?

Answer

+ kJ

Example 11

Which of the following are proper formation reactions?

  • Si(s) + 2 F2(g) → SiF4(g)
  • H2(g) + Cl2(g) → 2 HCl(g)
  • CaO(s) + CO2 → CaCO3(s)

Solution

Solution

  • In this reaction, one mole of a substance is produced from its elements in their standard states, so this is a proper formation reaction.
  • In this reaction, two moles of product are produced, so this is not a proper formation reaction.
  • One mole of a substance is produced, but it is produced from two other compounds, not its elements.

    So this is not a proper formation reaction.

Test Yourself

Is this a proper formation reaction? Explain why or why not.

2 Fe(s) + 3 P(s) + 12 O(g) → Fe2(PO4)3(s)

Answer

This is not a proper formation reaction because oxygen is not written as a diatomic molecule.

Given the formula of any substance, you should be capable to record the proper formation reaction for that substance.

Learning Objectives

Test Yourself

Is this a proper formation reaction?

Explain why or why not.

2 Fe(s) + 3 P(s) + 12 O(g) → Fe2(PO4)3(s)

Answer

This is not a proper formation reaction because oxygen is not written as a diatomic molecule.

Given the formula of any substance, you should be capable to record the proper formation reaction for that substance.

Learning Objectives

  • Define a formation reaction and be capable to recognize one.
  • Use enthalpies of formation to determine the enthalpy of reaction.

Saavedra M, Culotta R, Kamboj S, Chaney S and Lopez F.

What is a class 3 allergy

A Middle-aged Lady with an Anterior Mediastinal Mass and Respiratory Failure. J La State Med Soc (4) Jul-Aug ;

Niolet P, Vital C, Daberkow D, Beech S, Kumar P, Kamboj S, and Lopez F. Recurrent Pneumonia in a Middle-aged Lady. J La State Med Soc , November/December , –

Kamboj S, Harris J, Gupta S, Thakur V, Willis K, Espinoza C, and Lopez F. A 19 Year-old Man Presenting With A Generalized Body Rash. J La State Med Soc (3) May/June

Kamboj S, Lillis R, Wegmann M, Wild L, Lopez F, and Kumar P. Hereditary Angioedema: A Rare but Potentially Lethal Disease. J La State Med Soc May/June ,

Kamboj S, Gupta S, Kelly G, Helmcke F, and Lopez F. A Predictable Outcome of a Preventable Disease.

J La State Med Soc December , –

Kamboj S, Kumar P, Cai X, and Stallworth of Medications For Elderly In A Nursing Home. J La State Med Soc September , –

Substitution or Single Replacement Reactions A single free element replaces or is substituted for one of the elements in a compound. The free element is more reactive than the one its replaces.

Zn + 2 HCl > H2 + ZnCl2
zinc hydrochloric acid hydrogen zinc chloride

Cu + 2 AgNO3 > 2 Ag + Cu(NO3)2
copper silver nitrate silver copper (II) nitrate

H2 + 2 AgNO3 > 2 Ag + 2 HNO3
hydrogen silver nitrate silver nitric acid

2 Na + 2 H2O > 2 NaOH + H2
sodium water sodium hydroxide hydrogen

Senokot S

Generic Name:docusate and senna (DOK yoo sate and SEN a)
Brand Name:Doc-Q-Lax, Doculax, Dok Plus, Gentlax S, Peri-Colace, Senna Plus, Senna S, Sennalax-S, Senokot S, SenoSol-SS

Medically reviewed by on Dec 5, – Written by Cerner Multum

Saavedra M, Culotta R, Kamboj S, Chaney S and Lopez F.

A Middle-aged Lady with an Anterior Mediastinal Mass and Respiratory Failure. J La State Med Soc (4) Jul-Aug ;

Niolet P, Vital C, Daberkow D, Beech S, Kumar P, Kamboj S, and Lopez F. Recurrent Pneumonia in a Middle-aged Lady. J La State Med Soc , November/December , –

Kamboj S, Harris J, Gupta S, Thakur V, Willis K, Espinoza C, and Lopez F. A 19 Year-old Man Presenting With A Generalized Body Rash. J La State Med Soc (3) May/June

Kamboj S, Lillis R, Wegmann M, Wild L, Lopez F, and Kumar P. Hereditary Angioedema: A Rare but Potentially Lethal Disease. J La State Med Soc May/June ,

Kamboj S, Gupta S, Kelly G, Helmcke F, and Lopez F. A Predictable Outcome of a Preventable Disease.

J La State Med Soc December , –

Kamboj S, Kumar P, Cai X, and Stallworth of Medications For Elderly In A Nursing Home. J La State Med Soc September , –

Substitution or Single Replacement Reactions A single free element replaces or is substituted for one of the elements in a compound. The free element is more reactive than the one its replaces.

Zn + 2 HCl > H2 + ZnCl2
zinc hydrochloric acid hydrogen zinc chloride

Cu + 2 AgNO3 > 2 Ag + Cu(NO3)2
copper silver nitrate silver copper (II) nitrate

H2 + 2 AgNO3 > 2 Ag + 2 HNO3
hydrogen silver nitrate silver nitric acid

2 Na + 2 H2O > 2 NaOH + H2
sodium water sodium hydroxide hydrogen

Senokot S

Generic Name:docusate and senna (DOK yoo sate and SEN a)
Brand Name:Doc-Q-Lax, Doculax, Dok Plus, Gentlax S, Peri-Colace, Senna Plus, Senna S, Sennalax-S, Senokot S, SenoSol-SS

Medically reviewed by on Dec 5, – Written by Cerner Multum


How should I use Senokot S?

Use this medication exactly as directed on the label, or as prescribed by your doctor.

Do not use it in larger amounts or for longer than recommended.

Take this medication with a full glass of water.

It may be best to take this medication at night or at bedtime. Senokot S should cause you to own a bowel movement within 6 to 12 hours.

Do not take this medication for longer than 7 days in a row, unless your doctor tells you to.

Call your doctor if your constipation does not improve or if it gets worse after taking Senokot S.

Store Senokot S at room temperature away from moisture and heat.


Before taking this medicine

You should not use this medication if you are allergic to Senokot S, or if you are also taking mineral oil.

Ask a doctor or pharmacist about using Senokot S if you have:

  1. stomach pain;

  2. a sudden change in bowel habits that lasts for 2 weeks or longer; or

  3. nausea or vomiting;

  4. if you own an intestinal disorder such as Crohn’s disease or ulcerative colitis.

Do not use this medication without your doctor’s advice if you are pregnant.

It is not known whether docusate and senna passes into breast milk or if it could harm a nursing baby.

Do not use this medication without telling your doctor if you are breast-feeding a baby.

Ask a doctor before giving this medication to a kid younger than 2 years old.


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