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

Determine the reaction and balance the following equations urgent due in the morning

How do you determine the percent yield of a chemical reaction

What are the advantages of using the metric system? designed as a decimal system making conversions simpler more accurate system of measurement has prefixes that correspond to an amount to use with all base units used by the entire scientific community