National Dental Examining Board of Canada (NDEB) Practice Exam

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Prepare for the National Dental Examining Board of Canada (NDEB) Test. Study with flashcards and multiple choice questions, each question offers hints and detailed explanations. Achieve success in your exam!

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When gypsum is mixed with water, powder particles are replaced by crystals of?

Calcium carbonate
Calcium phosphate
Calcium sulfate
Calcium chloride

The correct answer is: Calcium sulfate

When gypsum is mixed with water, it undergoes a chemical reaction and forms crystals of calcium sulfate. Calcium carbonate, calcium phosphate, and calcium chloride are not the correct answers. Calcium carbonate is the main component of limestone and does not react with water. Calcium phosphate is a compound found in bones and teeth and is also not involved in the reaction with gypsum. Calcium chloride is soluble in water and does not form crystals. Overall, calcium sulfate is the only correct answer because it is the product of the reaction between gypsum and water.