If 25% of a radioactive element remains after 1,000 years, what is the half-life?

Which of the following is not a correct ionic formula unit? LiS2, KCL, BaO, Ca3N2

What happened after the gas syringe was inserted into the flask with the methane gas?

What exactly is an explosion

An atom of the element iron has an atomic number of 26 and an atomic weight of 56. if it is neutral, how many protons, neutrons, and electrons does it have?

New technology has made methods of transportation faster

For what reasons would modern scientists accept dalton's atomic theory but not the idea of an atom proposed by the greek philosophers?

Which physical method can be used for obtaining a sample of salt from a small beaker of salt water? boiling freezing chromatography sorting

Science is a unique field of thought because it relies on to describe the world. •Observations and experim •Teachers and students •Books and writings •Scientists and statements

Hemoglobin, a protein in red blood cells, carries o2 from the lungs to the body's cells. iron (as ferrous ion, fe2+) makes up 0.33 mass % of hemoglobin. if the molar mass of hemoglobin is 6.8 Ã 104 g/mol, how many fe2 + ions are in one molecule?

What could you predict about a methane molecule that would most likely be made by using both the quantum model of the atom and John Dalton's model?