After three half-lives, a sample contains 20 grams of parent isotopes. How many grams of the parent isotope were present to start?

Which in bigger 43 mg or 5 g

What is a diamond's scientific name

In what way are chemicals a part of our everyday lives

What is the estimated age of a tree with 6 dark rings and 6 light rings? 12 years old 3 years old 4 years old 6 years old

Cesium-137 and Strontium-90 are both produced in nuclear fallout. Cesium-137 has a half-life of 30 years. Strontium-90 has a half-life of 28 years. Strontium-90 is considered to be a greater health threat because cesium-137 has a longer half-life. a.

Which of he following is not a part of the peer review process or its result? A. Allowing scientists to share ideas through published work B. Making sure that a piece of work is correct and includes bias C.

An ion has a charge of 2 - and 18 electrons. A) From which atom does this ion form? B) How do you know?

What diseases are spread in warm temperatures?

In 1993 the Minnesota Department of Health set a health risk limit for chloroform in groundwater of 60.0 g/L Suppose an analytical chemist receives a sample of groundwater with a measured volume of 79.0 mL.

A good way for someone to identify similar substances is to measure their densities true or false