Title: The Effect of the Amount of Salt (Mass) on The Density of Coloured Solutions Question: How does the Amount of Salt Solution (Mass) Affect the Density of Liquid Solutions? Background Research: Density is how light or how heavy something is, depending on its size. Density can determine an object’s mass or volume. If an object is more dense, it will sink and its atoms would be closely packed. When an object is not dense, it will float which will make the atoms loose.
A volatile liquid can be easily converted to its gaseous state, the gas that forms from vaporization is known as vapor and it is assumed to behave as an ideal gas. One of the properties that characterize a volatile liquid is determination of its molar mass. Dumas method also known as the vapor density method uses the vapor density of the unknown volatile liquid in determining its molar mass. The major assumptions of these methods are the substance behaves ideally. The molar mass of a volatile liquid can be obtained by measuring the temperature, pressure, mass, and volume in a gaseous state.
Biology Design Practical Joshua Edwards What are effects of the volume of a potato and the amount of weight it loses when placed in salt solution? Introduction This design practical uses a potato’s surface area to volume ratio to see what affects it has on osmosis in different concentrations. Osmosis is the movement of water molecules through a cell membrane into an area of a higher solute concentration. The movement goes the way of the solvent with more solute because the lower solute concentration is drifting through balancing the ratio of solute per solvent (En.wikipedia.org, 2018). Surface Area to Volume Ratio shows the amount of area the entity has versus the amount of space inside the entity.
Modeling of Contact Angle for a Liquid in Contact with a Rough Surface When a solid is in contact with liquid, the molecular attraction will reduce the energy of the system below that for the two separated surfaces. This is expressed by the Dupré equation Figure-1 2.1 Wenzel Model: The Wenzel model (Robert N. Wenzel 1936) describes the homogeneous wetting regime, as seen in Figure 2, and is defined by the following equation for the contact angle on a rough surface. where is the apparent contact angle which corresponds to the stable equilibrium state (i.e. minimum free energy state for the system). The roughness ratio, r, is a measure of how surface roughness affects a homogeneous surface.
The contact angle of the film was measured with distilled water under room temperature. 2.10 Crosslink density () and average molecular weight between two crosslinks (Mc) Crosslink density () and average molecular weight between two crosslinks (Mc) were determined by the equilibrium swelling method according to the Flory-Rehner equation (Eq. 1). Toluene was chosen as a solvent for the calculations. Mc =-(ƥpVsØ1/3)/(ln(1-Ø)+ Ø+ƛØ2) (1) where Vs is the molar volume of the solvent, ƥp is the density of the polymer and Ø is the volume fraction of the polymer in the swollen state.
Thus the energy of surface molecules is higher, and the surface of liquid behaves like a stretched membrane exhibiting the property of surface tension, by virtue of which it tries to aquire the minimum surface area to attain lowest possible energy. Contact Angle Hysteresis: A liquid climbing up along some surface always has the leading angle of contact ( aL ) greater than or equal to the preceding angle of contact ( aP ). This difference in the angle of contacts aL-aP is called the Contact Angle Hysteresis. This difference in the angle of contact generates a net upward force opposite to gravity, allowing the liquid to move upwards.This is the principle behind why raindrops resist falling down a glass
The lubrication parameters that can be plotted with coefficient of friction are viscosity, sliding speed, sliding distance and load. The coefficient of friction is at its lowest in the hydrodynamic and thin film zones. At this point, the oil film is thick enough to ensure that there is no contact between asperities on the pin and disc surfaces. Moving to the right of the graph, which is in hydrodynamic zone, the oil film thickness is increasing due to increasing viscosity, increasing sliding speed and decrease in load whereas the coefficient of friction increase gradually. Besides, on the left of the curve, the asperities will start to rub against each other because of the oil film thickness decreases.
Analytical indices related to fats and oils can be distinguished as structure or quality indices. Structure indices are the iodine value (IV), a measure of total unsaturation of an oil or fat; the saponification value (SV), an indicator of average M.W. ; and the hydroxyl value (HV), which is applicable to fatty compounds (or their mixtures) containing (Knothe, 2002). Saponification is the hydrolysis of fats or oils under basic conditions to afford glycerol and the salt of the corresponding fatty acid (Chalmers and Bathe, 1978). The saponification number is the number of milligrams of potassium hydroxide required to neutralize the fatty acids resulting from the complete hydrolysis of 1g of fat.