Thursday, April 25, 2024
Home xin Xiaoming found a small paper bag in the food packaging bag, which said “quicklime desiccant, do not eat”. He took out the small paper bag

Xiaoming found a small paper bag in the food packaging bag, which said “quicklime desiccant, do not eat”. He took out the small paper bag

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inquiry 1: because calcium oxide will release a lot of heat when dissolved in water, take an appropriate amount of solid m and add it to the beaker containing water. The temperature has no obvious phenomenon, so fill in: solid m is invalid.
inquiry 2: because the aqueous solution of calcium hydroxide is alkaline, it can turn the colorless phenolphthalein test solution into red. Therefore, according to the conclusion, it can be inferred that the phenomenon is: the colorless phenolphthalein test solution turns red
(1) calcium oxide can react with water to form calcium hydroxide. Calcium hydroxide may also be just formed by the reaction between unmodified calcium oxide and water, so it is not tight, so fill in: it is not tight. Calcium hydroxide may be produced by the reaction of quicklime dissolved in water and water
(2) according to the conclusion, if the desiccant contains calcium carbonate, the reaction between calcium carbonate and hydrochloric acid will produce carbon dioxide gas, so the designed experiment is: take a small amount of desiccant and add an appropriate amount of dilute hydrochloric acid to observe the phenomenon. If bubbles are seen, it contains calcium carbonate
so fill in: calcium carbonate (or CaCO3); Put an appropriate amount of solid m into the test tube, then drop dilute hydrochloric acid, and immediately cover the mouth of the test tube with a glass sheet coated with lime water. If the lime water becomes turbid, it is proved that solid m contains calcium carbonate
(3) the chemical equation of possible reaction of calcium oxide modification is: Cao + H2O  Ca (OH) 2, CO2 + Ca (OH) 2  CaCO3 ↓ + H2O; So the answer is: Cao + H2O ↓ Ca (OH) 2, CO2 + Ca (OH) 2 ↓ CaCO3 ↓ + H2O

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