When you dissolve copper metal in nitric acid why must the reaction be performed in the hood?

Is a ping pong ball an element or a compound? What mixtures are chemical or physical change? What is hydrogen's bond angle? How do you separate muddy water from ink? What element has an electron configuration of 1s22s22p63s23p63d104s24p65s2? Why is diamond element? What are electropositive elements? Why is polutted water so difficult to clean? Which element has lowest destiny? How do you separate lead iodide precipitate and potassium nitrate solution? Is zirconium poisonous? Which intermolecular force would affect the melting point the least? How does smoking affect carbon dioxide levels? Do girls love to smell vinegar? Can you make jewelry out of each of the elements listed below? If you want to fade your pants lightly what is the best water-to-bleach ratio for about a 50 percent bleach? Is borax metalic or non metalicic? Iron 3 hydroxide formula? What does a 94lb bag of cement consist of? What is the second quantum number for the electrons in the 4p energy sublevel of bromine?

When you dissolve copper metal in nitric acid why must the reaction be performed in the hood?