An element has atomic number 10 and an atomic mass of 20. How many neutrons are in the atom of this element?

A. 10

B. 20

C. 30

D. 0

E. 200

Why do theories and model change over time?

You need to make an aqueous solution of 0.223 M barium bromide for an experiment in the lab, using a 250 mL volumetric flask. How much solid barium bromide should you add?

In a report to a supervisor, a chemist described an experiment in the following way: "0.0800 mol of H2O2 decomposed into 0.0800 mol of H2O and 0.0400 mol of O2.

How many mL of stomach acid (assume it is. 035 M HCI) can be neutralized by an antacid tablet containing. 231g Mg (OH) 2?

What mass of copper is deposited when a current of 10.0a is passed through a solution of copper (ii) nitrate for 30.6 seconds?

What Word means the gradual change and build up of organisms in an enviroment

If you see the Sun is high in the sky, what can you say about the SUN as viewed from the opposite side of Earth at the same moment?

What element has 8 valence electrons

Which of the following best describes a metal? Brittle, shiny, and solid Brittle, dull, and low density Malleable, shiny, and able to conduct heat or electricity Malleable, dull, and solid, liquid, or gas at room temperature?

Which of the following errors could cause your percent yield to be falsely high, or even over 100%? Select ALL that apply. A.) Heating the sample too vigorously. B.) Handling the crucible directly with your hands. C.