Which of the following ground-state electron configurations represents the atom that has the lowest first-ionization energy?

Which of the following are correct values for the ideal gas laws constant r

The number of moles of a given mass of a substance can be found without knowing its molecular formula or molar mass. true false

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?