Hello! Please help. Is air an element, compound, or mixture?
Is Hydrochloride Acid an element, compound, or mixture?
Oh if you can could you put the explanation of one of them, thanks!

When the volume and number of particles of a gas are constant which of the following is also constant

Why do oxygen have a strong attractive force for electrons

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.