Synthesis, Chemical Reactions, and Biological Chemistry Notes

Synthesis of Iron (II) Sulfide

• Nominative Chemical Transformation: This reaction describes the process of combining elemental iron and sulfur to create a compound.

• Nominative Equation:

  • $\text{Iron} + \text{Octasulfur} \rightarrow \text{Iron (II) Sulfide}$

• Chemical Equation:

  • $Fe + S_8 \rightarrow FeS$

• Balanced Chemical Equation (Equation-Bilan):

  • $8\,Fe + S_8 \rightarrow 8\,FeS$

• Physical States of Reactants and Products:

  • The reaction involves solid iron and solid sulfur to produce solid iron (II) sulfide:

  • 8\,Fe_{(s)} + S_8_{(s)} \rightarrow 8\,FeS_{(s)}

Reaction Between Lead (II) Chloride and Potassium Iodide ($PbCl_2$ and $KI$)

• Nominative Chemical Transformation: The reaction involves Lead (II) chloride ($PbCl_2$) and potassium iodide ($KI$) to produce Lead (II) iodide ($PbI_2$) and potassium chloride ($KCl$).

• Components Involved:

  • Lead atom ($Pb$)

  • Chlorine atom ($Cl$)

  • Potassium atom ($K$)

  • Iodine atom ($I$)

• Nominative Equation:

  • $\text{Lead (II) chloride} + \text{Potassium iodide} \rightarrow \text{Lead (II) iodide} + \text{Potassium chloride}$

• Chemical Equation:

  • $PbCl_2 + KI \rightarrow PbI_2 + KCl$

• Balanced Chemical Equation:

  • $PbCl_2 + 2\,KI \rightarrow PbI_2 + 2\,KCl$

• Physical States of Reactants and Products:

  • The reactants are in aqueous solution ($aq$), and the reaction produces a solid precipitate ($s$):

  • PbCl_2_{(aq)} + 2\,KI_{(aq)} \rightarrow PbI_2_{(s)} + 2\,KCl_{(aq)}

Reaction Between an Acid and a Metal

• General Description: Hydrochloric acid (Acide chlorhydrique) reacts with the metal magnesium to produce a gas and a salt.

• Specific Transformation: Hydrochloric acid reacts with magnesium ($Mg$) to form dihydrogen ($H_2$) and magnesium chloride ($MgCl_2$).

• Nominative Equation:

  • $\text{Hydrochloric acid} + \text{Magnesium} \rightarrow \text{Dihydrogen} + \text{Magnesium chloride (} MgCl_2 \text{)}$

• Chemical Equation:

  • $HCl + Mg \rightarrow H_2 + MgCl_2$

• Balanced Chemical Equation:

  • $2\,HCl + Mg \rightarrow H_2 + MgCl_2$

Biological Links: Cellular Respiration and Photosynthesis

• Cellular Respiration:

  • Description: Glucose reacts with dioxygen ($O_2$) to release energy, water, and carbon dioxide.

  • Nominative Equation: $\text{Glucose} + \text{Dioxygen} \rightarrow \text{Water} + \text{Carbon dioxide}$

  • Chemical Equation: $C_6H_{12}O_6 + O_2 \rightarrow CO_2 + H_2O$

  • Balanced Equation: $C_6H_{12}O_6 + 6\,O_2 \rightarrow 6\,CO_2 + 6\,H_2O$

• Photosynthesis:

  • Description: This is the inverse phenomenon of cellular respiration. It utilizes water and carbon dioxide to create glucose and dioxygen.

  • Nominative Equation: $\text{Water} + \text{Carbon dioxide} \rightarrow \text{Glucose} + \text{Dioxygen}$

  • Chemical Equation: $CO_2 + H_2O \rightarrow C_6H_{12}O_6 + O_2$

  • Balanced Equation: $6\,CO_2 + 6\,H_2O \rightarrow C_6H_{12}O_6 + 6\,O_2$

  • Result: The process yields one molecule of glucose and six molecules of dioxygen.

Exercises and Molecular Interpretation

• Balancing Polyatomic Equations:

  • Balanced equation: $Fe(OH)_3 + 3\,HClO_4 \rightarrow Fe(ClO_4)_3 + 3\,H_2O$

  • Reactant chemical formulas: $Fe(OH)_3$ and $HClO_4$.

  • Product chemical formulas: $Fe(ClO_4)_3$ and $H_2O$.

  • Reaction ratio: 1 molecule of $Fe(OH)_3$ reacts with 3 molecules of $HClO_4$ to form 1 molecule of $Fe(ClO_4)_3$ and 3 molecules of $H_2O$.

• Analysis of the reaction $2\,KI + HgCl_2 \rightarrow 2\,KCl + HgI_2$:

  • Number of types of molecules: 4 types are present in the reaction.

  • Products: $2\,KCl$ and $HgI_2$.

  • Total reacting molecules: 3 molecules react together (2 molecules of $KI$ and 1 molecule of $HgCl_2$) to form 3 product molecules (2 of $KCl$ and 1 of $HgI_2$).

• Atomic Composition Table:

  • $Fe_2O_3$: 2 atoms of $Fe$ and 3 atoms of $O$.

  • $6\,Cu_2O$: 12 atoms of $Cu$ and 6 atoms of $O$.

  • $5\,K_2Cr_2O_7$: 10 atoms of $K$, 10 atoms of $Cr$, and 35 atoms of $O$.

  • $3\,MgI_2$: 3 atoms of $Mg$ and 6 atoms of $I$.

  • $2\,Pb(OH)_4$: 2 atoms of $Pb$, 8 atoms of $O$, and 8 atoms of $H$.

  • $8\,Al_2O_3$: 16 atoms of $Al$ and 24 atoms of $O$.

  • $4\,C_6H_{12}O_6$: 24 atoms of $C$, 48 atoms of $H$, and 24 atoms of $O$.

  • $(NH_4)_3PO_4$: 3 atoms of $N$, 12 atoms of $H$, 1 atom of $P$, and 4 atoms of $O$.

• Chemical Formula Construction:

  • 1 atom of $Fe$ and 1 atom of $S \rightarrow FeS$

  • 2 atoms of $K$ and 1 atom of $O \rightarrow K_2O$

  • 2 atoms of $N$ and 3 atoms of $O \rightarrow N_2O_3$

  • 1 atom of $H$ and 1 atom of $Br \rightarrow HBr$

  • 1 atom of $Ca$ and 2 atoms of $Cl \rightarrow CaCl_2$

  • 1 atom of $Na$ and 1 atom of $Cl \rightarrow NaCl$

  • $(NH_4)_2SO_3$: Ammonium sulfite.

  • $Pb(NO_3)_2$: Lead (II) nitrate.

  • 1 iron atom and 2 groups containing 1 manganese and 4 oxygen atoms ($MnO_4$) $\rightarrow Fe(MnO_4)_2$