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Anonymous users2024-01-24(1) Starch is a carbohydrate composed of three elements: C, H and O.
2) The main component of scale in the water bottle is calcium carbonate, which can react with acidic substances and dissolve, and vinegar is acidic.
3) The main components of white sugar and brown sugar are sucrose Using the adsorption of activated carbon, brown sugar can be decolorized into white sugar
4) Sausages, salted duck, mustard, dried tofu and other foods sold on the market are often vacuum-packed, the purpose of which is to isolate the air, so as to prevent food from oxidizing and deteriorating
5) A is a metal material, B is an organic synthetic material, C is a metal material, D is a metal material, so B
6) Natural gas is a mixture, and its main component is methane; Methane is flammable and explosive, pay attention not to contact open flames or electric sparks, etc
(1) The "firewood" in the family kitchen tends to be clean, including gas, liquefied petroleum gas, and methane; >>>More
(1) It is known that the valency of potassium is +1 valence, and the valency of oxygen is -2 valence, according to the principle of valency (the algebraic sum of positive and negative valency in the compound is zero), then let the valency of iodine element be x, then (+1)+x+3 (-2)=0, and the solution is x=+5; >>>More
(3) The calcium content on the packaging bag refers to the content of the element rather than the content of elemental calcium, because the calcium salt contains calcium carbonate instead of calcium element, so the answer is: calcium. >>>More
(1) If the oil in the pot catches fire, the lid should be closed immediately to extinguish the fire, because the lid can isolate the air, so as to achieve the purpose of extinguishing the fire >>>More
How to hedge the toilet door at the door:
Solution: The entrance is the fundamental solution. >>>More