1. Tofu should not be cooked with spinach. Calcium oxalate is a precipitate that the human body cannot absorb. Spinach, onion and bamboo shoots are rich in oxalic acid and sodium oxalate, and tofu contains more calcium salts, such as calcium sulfate. The above substances can undergo a metathesis reaction to generate calcium oxalate precipitation and other substances.

2. The harm of aluminum to human health. Aluminum has always been considered as a non-toxic element, so aluminum drinking utensils, baking powder containing aluminum expansion agent and water purification agent are widely used.

3. It is not advisable to burn oil and smoke when cooking. When oil is at high temperature, polycyclic compounds are easily formed. Generally, vegetable oil contains more unsaturated fatty acids, which makes it easier to form polycyclic compounds. Experiments show that polycyclic compounds are easy to induce animal bladder cancer.

Extended data:

1, chemical characteristics:

Chemistry is one of the important basic sciences and a subject based on experiments. It develops rapidly with the mutual penetration of physics, biology, geography, astronomy and other disciplines, and also promotes the development of other disciplines and technologies.

2, the research object of chemistry:

Chemistry plays an important role in our understanding and utilization of matter. The universe is made of matter, and chemistry is one of the main ways and means for human beings to understand and transform the material world. It is a discipline with a long history and full of vitality, which is closely related to human progress and social development, and its achievement is an important symbol of social civilization.

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