Gypsum Products

A. Rapid spatulation results in decreased setting time
B. 2% potassium sulphate is accelerator
C. Citrates are retarders
D. All of the above

A. Not waiting for 20 min before pouring
B. High speed accelerator
C. Air incorporation in the mix
D. All of the above

A. Increased spatulation
B. Adding potassium sulfate
C. Less water powder ratio
D. Allowing setting under water

A. Na2 So4
B. Nacl
C. Citrales
D. K₂ So₄

A. Impression plaster
B. Model plaster
C. Stone plaster
D. Die stone

A. Testing the strength of plaster of paris
B. Evaluating the setting time of plaster of pris
C. Testing the metal hardness
D. Testing the purity of noble metals

A. Difference in solubility of CaSo4 ½ H2O + CaSO4+ 2H2O
B. Reaction between CaSO4+ 2H2O and water
C. Nucleation and growth of CaSo4 ½ H2O crystals
D. Reaction between hemihydrate and hihydrate

A. Impression plaster
B. Class I stone / Hydrocal
C. Class II stone/Densite
D. Model plaster

A. Is wet calcined hemihydrate
B. Has porous and irregular crystals
C. Is a – hamihydrate
D. Has a W / P of 0.2

A. 0.05
B. 0.10
C. 0.15
D. 0.20