131 53, You start out with some amount of this element and after 24 days you have 5 grams left. The half-life of this is 8 days. How much did you start with?​

Which is the best predictor of the radioactive nature of an isotope? o the proton-to-electron ratio the neutron-to-proton ratio o the neutron-to-electron ratio the electron-to-proton ratio

What is the power rating of the lightbulb if 3.0 a flow through it when connected to a 15 v battery

The first-order reaction a→2b+c has rate constant 0.538 s−1. if the initial concentration of a is 0.867 mol l−1, what is the half-life of the reaction in seconds? remember to use correct significant figures in your answer (round your answer to the nearest hundredth). do not include units in your response.