If 3.0 grams of strontium-90 in a rock sample remained in 1989, approximately how many grams of strontium-90 were present in the original rock sample in 1933?

Separation techniques in analytical chemistry

Round off 0.0008769 to three significant digits.

Without doing any calculations, determine which sample contains the most atoms. a. a 1-g sample of thorium b. a 1-g sample of boron c. a 1-g sample of zinc

17 p 18 n What is the atomic number of this element?

A brick lies perilously close to the edge of the flat roof of a building. The roof edge is 50 ft above street level, and the brick has 370.0 J of potential energy with respect to street level.

The data below were collected for the following reaction at 500 ∘C: CH3CN (g) →CH3NC (g) Time (h) [CH3CN] (M) 0.0 1.000 5.0 0.794 10.0 0.631 15.0 0.501 20.0 0.398 25.0 0.

How do i convert 3.00 moles H2 to molecules?

How can you use the chemical formulas for sucrose (C6H, 20,) and rust (Fe, O,) to classity them ionic or molecular compounds?

What is true of energy as is passes through an ecosystem? a. All of the energy in an organism is used by the animal that eats it. b. Any stored energy in an organism is used by the animal that eats it. c.

Which can associate a suspect and the firing of a gun? (its not b) A) markings on the gun's exterior B) markings on the casing C) markings on the bullet D) powder residues