Agricultural Chemistry and Biochemistry Review

Comprehensive practice flashcards covering chemical solutions, salt hydrolysis, soil sorption, plant biochemical components, carbohydrates, lipids, and amino acids.

What is the hydrolysis of salts?

It is a protolytic reaction of dissolved salt ions with water molecules that produces hydroxide ($OH^-$) or hydrogen ($H^+$ / $H_3O^+$) ions, resulting in an acidic or basic reaction in the solution.

What type of reaction does an aqueous solution of ammonium nitrate ($NH_4NO_3$) have, and what is its hydrolysis equation?

It exhibits an acidic reaction (derived from a weak base and a strong acid), described by the reaction: $NH_4NO_3 + H_2O \rightleftharpoons NH_4OH + HNO_3$ ($NH_4^+ + NO_3^- + H^+ + OH^- \rightarrow NH_4^+ + OH^- + H^+ + NO_3^-$).

What is the difference between nitrate nitrogen and saltpeter nitrogen?

There is no difference (none).

What are buffer solutions (purfačné roztoky)?

Solutions capable of dampening pH fluctuations and maintaining a constant pH value even after the addition of a small amount of a strong acid or base, based on the principle of neutralization.

How does an acetate buffer act in an acidic environment according to the provided reaction?

$$CH_3COOH + CH_3COO^- + K^+ + H^+ + Cl^- \rightarrow 2CH_3COOH + K^+ + Cl^-$$

Which elements are listed as macroelements?

C, H, N, P, S, O, Ca, Mg, K.

What are the primary nitrogenous substances found in plants?

Amino acids, peptides, proteins, glutenins (gluteíny), prolamins (prolamíny), and albumins (albumíny).

What is an aldosaccharide (aldosacharid)?

A monosaccharide with a carbon skeleton terminated by an aldehyde group, which makes it an aldehyde.

How is sucrose (beet sugar) classified?

As a disaccharide.

What does the carboxylic acid notation 16:0 mean, and which acid does it represent?

It indicates the ratio of the number of carbon atoms to the number of double bonds (16 carbon atoms and 0 double bonds); it represents palmitic acid (kyselina palmitová).

What chemical structure is depicted in the image?

The general formula of an amino acid ($R-\text{CH}(NH_2)-\text{COOH}$).

Which colligative property of solutions gives plants a better ability to resist freezing?

Freezing point depression of solutions (zníženie teploty tuhnutia roztokov).

Which ion is responsible for increasing the acidity of solutions?

Hydrogen cations ($H^+$); the higher the concentration of hydrogen cations, the more acidic the solution is.

By what process is atmospheric $CO_2$ concentration reduced, and what is its balanced equation?

Photosynthesis: $6CO_2 + 12H_2O + \text{solar energy} \rightarrow C_6H_{12}O_6 + 6H_2O + 6O_2$.

Which salts do not hydrolyze and why?

Salts derived from strong acids and strong bases; they do not hydrolyze because they are completely dissociated into ions, do not react with cations or anions, and the resulting reaction medium is neutral (pH is neutral).

Which elements belong to the invariable primary elements?

O, C, H, N, P, S, Na, Ca.

What are the primary non-nitrogenous substances in plants?

Starch, cellulose, lignin, and hemicellulose.

What is a ketosaccharide (ketosacharid)?

A monosaccharide containing one ketone (carbonyl) group in its molecule.

How is raffinose (rafinóza) classified?

As a trisaccharide.

What does the carboxylic acid notation 18:2 (9c, 12c) indicate, and which acid is it?

It indicates 18 carbon atoms, 2 double bonds, with double bonds positioned at carbons 9 and 12; it is linoleic acid (kyselina linolová).

Which amino acids are listed as essential?

Valine, leucine, isoleucine, threonine, methionine, lysine, phenylalanine, tryptophan, histidine, arginine, and selenocysteine.

What is the cationic and anionic composition of the soil solution specified in the notes?

Cations: $Ca^{2+}$, $Mg^{2+}$, $Na^{2+}$; Anions: $HCO_3^-$, $CO_3^{2-}$, $NO_3^-$.

Based on which colligative property of solutions can the adulteration of milk with water be detected?

Freezing point depression of solutions (zníženie teploty tuhnutia roztokov).

Which ion is responsible for increasing the basicity of solutions?

Hydroxide anions ($OH^-$); the greater the concentration of $OH^-$ anions, the more basic the solution is.

Which carbon cycle process leads to an increase in atmospheric $CO_2$ concentration?

Respiration (dýchanie).

What is the hydrolysis reaction of aluminium sulfate, $Al_2(SO_4)_3$?

$$Al_2(SO_4)_3 + 6H_2O \rightarrow 2Al(OH)_3 + 3H_2SO_4$$

How are homogeneous and heterogeneous systems defined?

If a system is composed of a single phase, it is homogeneous; if it is composed of several phases, it is heterogeneous.

What are the three types of soil sorption and their mechanisms?

1. Chemical sorption: The soil's ability to retain ions from chemical reactions occurring in the soil by forming sparingly soluble to insoluble precipitates.
2. Physicochemical (exchange) sorption: Ion exchange between the soil sorption complex and the soil solution.
3. Physical sorption: Surface forces of soil particles binding nutrients (fixation within clay mineral crystal lattices).

What process is shown in the chemical equation provided in the image?

The formation of a peptide bond between two amino acids, yielding a peptide and releasing water: $R_1-\text{COOH} + H_2N-R_2 \rightarrow R_1-\text{CO}-\text{NH}-R_2 + H_2O$.

What does the carboxylic acid notation 18:0 signify, and what is the acid's name and formula?

It denotes an 18-carbon chain with 0 double bonds; it represents stearic acid with the formula $CH_3(CH_2)_{16}COOH$.

What cations and anions are formed by the dissociation of sulfuric acid ($H_2SO_4$)?

Two hydrogen cations ($2H^+$) and one sulfate anion ($SO_4^{2-}$): $H_2SO_4 \rightarrow 2H^+ + SO_4^{2-}$.