A sample of helium has a volume of 325 mL and a pressure of 655 mmHg. What will be the pressure, in mmHg, if the sample of helium is compressed to 125 mL (T, n constant) ? (Show calculations.)

Radium-226 is a common isotope on earth, but it has a half-life of about 1620 years. given that earth is some 5 billion years old, why is there any radium at all?

When researchers need to prepare many reactions for polymerase chain reaction (PCR) amplification, they often create a "master mix" solution.

Which of the following would be considered a solution? A. salt in the sugar bowl B. sugar added to water C. oil added to water D. any fat-soluble substance mixed with any water-soluble substance

An elements atomic number is 117 how many electrons would an atom of this element have?

An isotope undergoes radioactive decay by emitting radiation that has no mass. What other characteristic does the radiation have? a. some shielding required b. positive or negative charge c. low penetrating power d. no charge

Originally, the periodic table was arranged by increasing atomic radius increasing atomic mass increasing atomic number increasing number of electrons

How many moles are in 15.5-g SiO2

Is Oxygen - O2 a pure substance or a mixture?

What atom has 14 protons and 14 electrons

What is a diagram showing the forces acting on a coasting bike rider traveling at 25 km/h on a flat roadway