Need !

which of the following is true about the concept of half-life?

a. half-life measures the rate of decay of a radioisotope.

b. the shorter the half-life, the more dangerous the radioisotope.

c. half-life predicts which atoms in a radioactive sample will decay.

Let the ed50 of a recreational drug be defined as the amount required for 50% of a test group to feel high or get a buzz. if the ed50 value of ethanol is 470 mg/kg body mass, what dose would a 70 kg party goer need to quickly consume in order to have a 50% chance of getting a buzz? 235 mg 470 mg 32,900 mg 35,000,000 mg

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ

How many moles of potassium are needed to react completely with 12.8 moles of magnessium bromide?