MISC 03 - Finals Quiz Flashcards
The boundary between two phases is generally described as an interface (True or false)
True
For the majority of liquids, an increase in temperature leads to an increase in surface tension (True or false)
False (Increased temperature, decreased surface tension)
The interfacial tension between two immiscible liquids arises as a result of imbalance of forces, in an identical manner to the surface tension between a liquid and its vapor (True or false)
True
Spreading occurs when the liquid placed on, for example, a water surface adheres to the water more strongly than it coheres to itself (True or false)
True
An increase in the concentration of the solute will cause an increase in the amount of absorption that occurs at equilibrium until a limiting value is reached (True or false)
True
Adsorption is generally exothermic, and hence an increase in temperature leads to a decrease in adsorption (True or false)
True
An increased surface area, achieved by a reduction in particle size or the use of a porous material, will decrease the extent of adsorption (True or false)
False (Increased surface area, increased extent of adsorption)
The lower the HLB of an agent, the more hydrophobic it is (True or false)
True
The ability of the micelles to increase the solubility of materials that are normally insoluble, or only slightly soluble, in the dispersion medium is termed as solubility (True or false)
False (Solubilization)
A physically adsorbed gas can be desorbed from a solid by decreasing the temperature and increasing the pressure (True or false)
False (Increasing temperature, decreasing pressure)
The contact angle between a liquid and a solid may be 0° signifying incomplete wetting, or may approach 180°, at which wetting is complete (True or false)
False (0° signifies complete wetting)
As the concentration of electrolyte present in the system is increased, the degree of flocculation increases, while wetting decreases (True or false)
True
Carboxymethylcellulose, Carbopol 934, Veegum, Tragacanth, and Bentonite are examples of flocculating agents (True or false)
False (Suspending agents)
The velocity of sedimentation is expressed by Stoke’s law (True or false)
True
Caking commonly occurs in emulsion (True or false)
False (Suspensions)
The study of flow which addresses the viscosity characteristics of powders, fluids, and semisolids is micromeritics (True or false)
False (Rheology)
The relationship the rate depends on amounts of reactants is shown by reaction constant (True or false)
False (Rate law, not reaction constant)
The average rate of the reaction over each interval is the change in concentration divided by the change in time (True or false)
True
The average rate decreases as the reaction proceeds because as the reaction goes forward, there are fewer collisions between product molecules (True or false)
False (Reactant molecules)
At higher temperatures, reactant molecules have less kinetic energy, move faster, and collide more often and with greater energy (True or false)
False (More kinetic energy)