What is the half life of a radioisotope of a 50g sample becomes a 25g after 18 days?

When an ionic compound dissolves in water, the ions are held to the water molecule due to A. an ionic bond. B. a covalent bond. C. an attractive force.

What is an atom made up and how are atoms of different elements from each other

1) One mole of particles of any substance contains how many particles? A) particles B) 3 * C) 3 * D) 6.02 * E) 6.02 * particles particles particles particles

Which statement accurately describes nonrenewable energy sources? a type of resource located only in the United States a group of resources found both above and below the earth's surface a group of resources made of inorganic matter a resource that

How is gamma radiation different from other types of electromagnetic radiation

Find the mass of 1 mole of cuprous oxide, or cu2o. assume the atomic mass of copper is 64 and oxygen is 16.

Ice (H2O) melting at 273 K and 1 atm has = 6.01 kJ/mol and = 6.01 kJ/mol while water vaporizing under the same conditions has = 37.6 kJ/mol and = 40.7 kJ/mol. Why is there such a large difference between and, but not for and?

What happens to the charges when an ionic compound forms

We dissolve 93 grams of sodium sulfate (Na2SO4) in 20 grams of water. What is the percent by mass of sodium sulfate in this solution? Answer in units of %.

The modern atomic model includes electrons orbiting the nucleus. which of the following parts of dalton's atomic model was disproved by the discovery of the electron? - atoms are tiny particles. - atoms cannot be divided into smaller parts.