A rock has 43.75 grams of Rb-87 and 306.25 grams of Sr-87, how many half-lives has it gone through?

Use the drop-down menus to answer each question. which runner finished the 100 m race in the least amount of time? which runner stopped running for a few seconds during the race? at what distance did anastasia overtake chloe in the race?

Suppose you have designed a new thermometer called the x thermometer. on the x scale the boiling point of water is 129 ? x and the freezing point of water is 13 ? x. part a at what temperature are the readings on the fahrenheit and x thermometers the same?

Rank the following four acids in order of increasing bronsted acidity : h2f+ , ch3oh, (ch3)2oh+ , ch3sh2+