A sample contains 2.2 g of the radioisotope niobium-91 and 15.4 g of its daughter isotope, zirconium-91. how many half-lives have passed since the sample originally formed?

atomc radius follow along the periodic table

A sample with ss = 40 and a variance of 8 has n = 5 scores. a. True b. False

Where is insulin produced? A. stomach B. pancreas C. large intestine D. small intestine

How many liters of nitrogen gas are needed to react with 90.0 g of potassium at STP in order to produce potassium nitride according to the following reactions?

Hydrogen peroxide rapidly decomposes to water and oxygen. If the water is appearing at a rate of 2.0 M/s, what is the rate of the reaction? 2H2O2 (g) - -> 2H2O (g) + O2 (g) Group of answer choices

1. What is the probability of rolling a five on one die three times in a row? 2. The allele for a cleft chin, C, is dominate among humans. Using a punnet square, what are the results of a cross between parents with genotypes Cc and cc

A chemical is placed in a beaker containing 20 g of soil and 500 mL of water. At equilibrium, the chemical is found in the soil ast a concentration of 100 mg. kg-1 of soil.

A solid reactant is placed into a beaker of warm water. The liquid vigorously bubbles as the soild dissolves into the solution. What will most likely happen if the temperature of the liquid is slightly reduced

How does the space between atoms change as agas goes through prase changes to become a soild? how. do they different? use words to describe

What is an endothermic reaction? O A. A reaction that produces heat O B. A reaction that uses radiation waves C. A reaction that absorbs heat O D. A reaction that contains enthalpy