20.500.12556/RUL-170056 Maksimum gostote vode in vodnih mešanic z alkoholi magistrsko delo Maximum Density of Water and Aqueous Alcohol Mixtures V magistrskem delu smo preučevali vpliv dodatka različnih alkoholov na vrednost maksimalne gostote in temperaturo, pri kateri je ta vrednost dosežena za različne mešanice vode in alkohola pri nizkih temperaturah (1–6 °C). Pripravili smo mešanice vode z alkoholom (metanol, etanol, propan-1-ol, propan-2-ol, 2-metilpropan-1-ol, 2-metilpropan-2-ol, 2,2-dimetilpropan-1-ol, butan-1-ol, butan-2-ol, 2-metilbutan-1-ol, 2-metilbutan-2-ol, 3-metilbutan-1-ol, 3-metilbutan-2-ol ter niza pentanolov) pri različnih molskih deležih alkohola (x) v razponu od ~0,001 ≤ x do območja topnosti alkohola v vodi. Gostoto smo merili z gostotomerom Anton Paar DSA 5000 M in z interpolacijo kvadratne funkcije določili temperaturo maksimalne gostote (Tₘₐₓ) ter vrednost maksimalne gostote (ρₘₐₓ). Mešanice smo razdelili v tri skupine glede na dolžino ogljikove verige (C₁–C₃, C₄, C₅). Rezultati kažejo, da pri nizkih koncentracijah metanola, etanola in propanolov pride do rahlega zvišanja Tₘₐₓ v primerjavi s čisto vodo (ΔT > 0), Tₘₐₓ pa se z večanjem molskega deleža alkohola zniža. Pri alkoholih s štirimi in petimi ogljiki Tₘₐₓ že ob minimalnih dodatkih alkohola upade (ΔT < 0). V vseh primerih se ρₘₐₓ z večanjem deleža alkohola posplošeno zmanjšuje. Delo prispeva k boljšemu razumevanju vodikovih vezi in Van der Waalsovih interakcij v mešanicah vode z alkoholi ter ponuja osnovo za razvoj kvantitativnih termodinamičnih modelov. In the master's thesis, we investigated the influence of the addition of various alcohols on the value of the maximum density and the temperature at which this maximum is reached for different aqueous alcohol mixtures at low temperatures (1–6 °C). We prepared mixtures of water and different alcohols (methanol, ethanol, 1-propanol, 2-propanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 2,2-dimethyl-1-propanol, 1-butanol, 2-butanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-1-butanol, 3-methyl-2-butanol and a series of pentanols) at various alcohol mole fractions (x) ranging from ~0.001 ≤ x up to the solubility limit of the alcohol in water. The density was measured using an Anton Paar DSA 5000 M densimeter, and by interpolating a quadratic function, we determined the temperature of maximum density (Tₘₐₓ) and the corresponding value of the maximum density (ρₘₐₓ). The mixtures were divided into three groups based on the length of the carbon chain (C₁–C₃, C₄, C₅). The results show that at low concentrations of methanol, ethanol, and propanols, there is a slight increase in Tₘₐₓ compared to pure water (ΔT > 0); however, as the alcohol mole fraction increases, Tₘₐₓ decreases. In alcohols with four and five carbon atoms, Tₘₐₓ decreases already with minimal alcohol additions (ΔT < 0). In all cases, ρₘₐₓ generally decreases with increasing alcohol content. This work contributes to the understanding of hydrogen bonding and Van der Waals interactions in aqueous alcohol mixtures and provides a foundation for the development of quantitative thermodynamic models. gostota temperatura voda alkohol mešanice voda-alkohol maksimum gostote density temperature water alcohol aqueous alcohol mixtures maximum density true false false K. Pavlin Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-07-02 12:39:45 2025-07-02 12:39:46 2025-07-04 11:45:23 0000-00-00 00:00:00 2025 0 Ljubljana 0 Ljubljana 133 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 543.318(043.2) 184991 241437955 40687.pdf 40687.pdf 1 61D8D3B243FA59A77BF5F3216BB48BCC a536358b853bcb4d43a302e80faea8f99a49fc4fd3e3d862b330d49480134998 fa03a834-572e-11f0-b232-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=211980 Pedagoška fakulteta 0 0 0