Química

Métodos básicos de visualización de micro y nanoescructuras con el microscopio de fuerza atómica (AFM)

Principio

Aproximando una punta aguda de silicona montada en un voladizo (cantilever) para tomar una muestra de una superficie se produce una interacción a escala  atómica. El resultado es que el voladizo se curva, lo cual se detecta con láser. En modo ...

Determinación de la masa molar de un líquido



Principle

The molar mass of a liquid is to be determined by evaporating a liquid at constant temperature and pressure, and measuring the volume of  vapour  formed using a calibrated gas syringe.

Benefits

• For both demonstration and student experiments
• Simple ...

Determinación del peso molecular de un polímero por medio de viscosidad intínseca



Principle

The viscosity of a liquid is effectively determined by the strength of the intermolecular attractive forces. In the case of solutions, the viscosity of the solvent can alter significantly depending on the type and concentration of the solute. Due to their size, ...

Condensación de los gases através del aumento de la presión y del enfriamiento

Principle

Gases are condensing when they are cooled and at high pressure. In this experiment butane is condensed by cooling it to ca. -15 °C. In the second part of the experiment butane is condensed by compressing it.

Benefits

• Compact setup
• Perfect as ...

Determinación de la entalpía de vaporización de líquidoscon Cobra4

Principle

The vaporisation of a liquid occurs with heat absorption. To determine the enthalpy of vaporisation, a known mass of the liquid which is to be investigated is vaporised in a special vaporisation vessel in a current of air. The quantity of heat absorbed, which corresponds to the ...

Volúmenes molares parciales

Principle

Due to intermolecular interactions, the total volume measured when two real liquids (e.g. ethanol and water) are mixed deviates from the total volume calculated from the individual volumes of the two liquids (volume contraction). To describe this non-ideal behaviour in the ...

Determinación de la entapía de mezclas de mezclas de fluídosbinarios con Cobra4

Principle

When two miscible liquids are mixed, a positive or negative heat effect occurs, which is caused by the interactions between the molecules. This heat effect is dependent on the mixing ratio. The integral mixing enthalpy and the differential molar mixing enthalpy can be determined ...

Determinación de entalpía de hidratación de un electrolito (ntalpía de solución ) con Cobra4

Principle

When a solid electrolyte dissolves in water, a positive or negative heat effect occurs as a result of the destruction of the crystal lattice and the formation of hydrated ions. The enthalpy of hydration of copper sulphate can be calculated from the different heats of reaction ...

Determinación de entalpía de neutralización con Cobra4

Principle

When a strong acid is neutralised with a strong base in dilute solution, the same amount of heat is always released. If the reaction takes place under isobaric conditions, this heat is known as the enthalpy of neutralisation. The chemical reaction which generates this heat is ...

Determinación de entalpía de fusión de una sustancia pura con Cobra4

Principle

When a solid melts, energy is required for the destruction of the crystal lattice. A substance whose melting point lies slightly below room temperature is first cooled until it solidifies and then melted in a calorimeter. The melting enthalpy is calculated from the decrease in ...

Elevación del punto de ebullición - Ley de Raoult con Cobra4

Principle

Raoult's law states: The vapour pressure of an ideal solution is directly dependent on the vapour pressure of each chemical component and the mole fraction of the component present in the solution.
That's why the boiling point of a solution is always higher than that of the pure ...

DETERM. DEL PODER CALORÍF. DE COMBUSTIÓN DE SOLIDOS Y GASES

• Glass jacket system easily expandable
• Illustrative experimental setup

Determinación del calor de formación de agua

Principle

Standard molar enthalpies of formation Δ_BH^Φ are important compiled thermodynamics tabulation quantities for calculating standard enthalpies of reaction for any arbitrary reaction. They are defined as the heat of reaction occurring in the direct formation of one mole of ...

Determinación del calor de formación de CO2 y CO

Principle

The standard molar enthalpies of formation Δ_BH^Φ are important compiled thermodynamic tabulation quantities for calculating standard enthalpies of reaction for any arbitrary reaction. They are defined as the heat of reaction occurring in the direct formation of one mole ...

Ley de Hess con Cobra4

Principle

The standard molar enthalpies of formation Δ_BH^Φ are important compiled thermodynamic tabulation quantities for calculating standard enthalpies of reaction for any arbitrary reaction. They are defined as the heat of reaction occurring in the direct formation of one mole ...