Why are the halogen elements so dangerous in their uncombined forms?

Discuss the law of conservation of matter

Is condensation of ethanol a physical change or a chemical change

Which element has the largest atomic radius? As N P Sb

Consider a hydrogen atom in the ground state. What is the energy of its electron? which is, - 2.1799 X10^-18 J Now consider an excited-state hydrogen atom. What is the energy of electron in the n=2 level?

Is steel wool an element, compound, or mixture

We are all familiar with the general principles of operation of an internal combustion engine: the combustion of fuel drives out the piston.

A first order reaction has a rate constant of 0.816 at 25 oC. Given that the activation energy is 22.7 kJ/mol, calculate the rate constant at 34 oC. (enter answer to 3 decimal places)

Part b select the ester that is formed when propanoic acid reacts with isopropyl alcohol in the presence of heat and an acid catalyst.

Do metals form anions or cations

Which of the following gases in Earth's atmosphere would you expect to find as molecules and which as individual atoms? a. Nitrogen b. Oxygen c. Argon