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Solid State Chemistry Mcqs

Q:

In thermogravimetric analysis, the result obtained appear as a __________

A) Continuous chart B) Continuous parabola
C) Continuous circular positions D) Discontinuous chart
 
Answer & Explanation Answer: A) Continuous chart

Explanation: Thermogravimetric is a technique for measuring the change in weight of a substance as a function of temperature or time, the result usually appears a continuous chart record, a schematic, typical, single step decomposition reaction.

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660
Q:

Which of the following option is appropriate for the TGA and DTA?

A) TGA and DTA measures only weight B) TGA measures only weight while DTA measures other effects
C) TGA and DTA measures only temperature D) TGA measures only temperature while DTA measures other effects
 
Answer & Explanation Answer: B) TGA measures only weight while DTA measures other effects

Explanation: DTA is more versatile than TGA, TGA detects effects which involve weight changes only. DTA also detects such effects in addition, detects other effects such as polymorphic transitions, which do not involve changes in weight.

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626
Q:

During the reactivity of solids, two stages that may usually be identified are Nucleation of the product and its subsequent growth. When is nucleation facilitated?

A) When there is a structural similarity between the products B) When there is structural similarity between the reactants
C) When there is structural dissimilarity between the product and the reactant D) When there is structural similarity between the product and the reactant
 
Answer & Explanation Answer: D) When there is structural similarity between the product and the reactant

Explanation: Nucleation is facilitated if there is structural similarity between the product and one or both of the reactants because this reduces the amount of structural reorganization that is necessary for nucleation to occur.

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546
Q:

Which of the following parameters can be used, using the DSC and DTA cells?

A) Catalytic properties of enzyme B) Elasticity of crystals
C) Enthalpy of substances D) Line positions of phases
 
Answer & Explanation Answer: C) Enthalpy of substances

Explanation: With DSC cells or with DTA cells that have been designed for a calorimetric response such measurements may be made rather more accurately and in addition the heat capacity of substances or phases may be measured as a function of temperature.

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448
Q:

Thermal analysis is defined as ___________

A) Measurement of concentration of materials as a function of temperature B) Measurement of solubility of materials as a function of temperature
C) Measurement of physical properties as a function of temperature D) Measurement of line positions of crystals as a function of temperature
 
Answer & Explanation Answer: C) Measurement of physical properties as a function of temperature

Explanation: Thermal analysis is defined as the measurement of physical and chemical properties of materials as a function of temperature. In practice, however the term thermal analysis is used to cover certain specific properties only. These are enthalpy, heat capacity, mass and coefficient thermal expansion.

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426
Q:

For the preparation of polycrystalline solids (i.e. powder), a mixture of solid starting materials directly react with each other in the solid state. What is the range of the temperature usually required for the solids to react together in Celsius?

A) 25 to 37 B) 1000 to 1500
C) -25 to 0 D) 2000 to 3000
 
Answer & Explanation Answer: B) 1000 to 1500

Explanation: Solids don’t react usually at room temperature over normal scale timescale, It is required to heat them at much higher temperature often 1000?C to 1500?C, in order for a reaction to occur at an appreciable rate.

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413
Q:

The appropriate relation between the surface area of any solid with that of the particle size can be stated as

A) Surface area of any solid increases with increase in particle size B) Surface area of any solid is always equal to the particle size
C) Surface area of any solid increases with decrease in particle size D) Surface area of any solid doesn’t depend at all on the particle size
 
Answer & Explanation Answer: C) Surface area of any solid increases with decrease in particle size

Explanation: Surface area is always inversely related with the particle size. In the form of a single crystal, a few grams of solid has a surface area about to equal to the area of a large postage stamp. In the form of a finely divided powder, its surface area is about equal to the area of a hundred meter running track. Hence surface area increases with decrease in particle size.

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353
Q:

During DTA (Differential thermal analysis) what kind of reference material is used?

A) Chemically active B) Physically active
C) Inert D) Having catalytic property
 
Answer & Explanation Answer: C) Inert

Explanation: Differential thermal analysis is a technique in which the temperature sample is compared with that of an inert material during a programmed change of temperature.

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