Is a marshmallow turning black when toasted a physical or chemical change?

The half-life of a certain radioactive material is 42 days. An initial amount of the material has a mass of 49 kg. Write an exponential function that models the decay of this material. Find how much radioactive material remains after 8 days.

Within one period, which group has the lowest first ionization energy? A) alkaline earth metals B) noble gases C) alkali metals D) halogens E) carbon family

Rutherford's experiment showed that some substances allowed alpha particles to pass through them Frequently. he theorized this happened because the nuclei were.

Which term best represents the models that explain and give the underlying causes for conclusions drawn from many years of experimental evidence? a) law b) hypothesis c) observation d) theory

How many moles of gas occupy 98 L at a pressure of 2.8 atmosphere and a temperature of 292 K

Which of the following is not true of science? 1. Science offers proof of a claim 2. Science is a way of knowing 3. Science is a process 4. Science provides support or fails to provide support to claim

What happens to the velocity of a sound wave in air if the temperature of the air increases

Determine the [oh-] concentration of a 0.741 m koh solution at 25°c.

In the lab, students decomposed a sample of calcium carbonate by heating it over a Bunsen burner and collected carbon dioxide according to the following equation: CaCO3 (s) CaO (s) CO2 (g) (a) How many mL of carbon dioxide gas were generated by the

J. J. Thomson A) Electrons are in orbital levels. John Dalton B) Atoms are the smallest unit of an element. Ernest Rutherford C) Electrons are scattered within the atom. Niels Bohr D) Protons are at the center of an atom.