The furnace and lid of traditional popcorn machines are made of lead-containing pig iron. Lead is easily volatilized and mixed into the popcorn when heated in a closed manner; automobiles use lead-con

The furnace and lid of traditional popcorn machines are made of lead-containing pig iron. Lead is easily volatilized and mixed into the popcorn when heated in a closed manner; automobiles use lead-containing pig iron. A. The lead in the pig iron in the furnace of the popcorn machine is extremely volatile, indicating that the melting point of lead is relatively low. Incorrect.

B. Lead in plants enters the human body along the food chain, and is mainly absorbed into the bloodstream through the small intestine. correct.

C. The method for calculating the mass fraction of an element is: multiply the relative atomic mass of the element's atoms by the number of atoms contained in a molecule, divide by the relative molecular mass, and multiply by one hundred percent; < /p>

The sum of the relative atomic masses of carbon atoms is: 12×10=120, the sum of the relative atomic masses of hydrogen atoms is: 1×12=12, and the sum of the relative atomic masses of calcium atoms is: 40×1=40 , the sum of the relative atomic masses of nitrogen atoms is: 14×2=28, the sum of the relative atomic masses of sodium atoms is: 23×2=46, the sum of the relative atomic masses of oxygen atoms is: 16×8=128, the relative molecular mass is Certain, so the smaller the sum of relative atomic masses of atoms, the smaller the mass fraction of the element. Because the sum of relative atomic masses of hydrogen atoms is the smallest, the mass fraction of hydrogen element is the smallest. It should be b representing hydrogen element. Incorrect.

D. The soluble substance formed by the combination of calcium and sodium EDTA and blood lead is eventually excreted from the body with the blood through the kidneys and urethra. Incorrect.

So choose: B.