A helium balloon contains 0.46g off helium. how many moles of helium does it contain?

The element in Period 3 that has the lowest first ionization energy is

Why are concentration units of mole fraction used in some colligative properties calculations? a. Mole fraction expresses concentration more accurately than molarity. b. Mole fraction does not depend on the chemical identity of the solute. c.

A compound is found to contain 6.1% hydrogen and 93.9% oxygen. Find it's empirical formula.

When phenolphthalein indicator is added to a colorless solution with a pH of 10, a student observes and concludes that the tested solution 1 remains colorless and is basic 2. remains colorless and is acidic 3. turns pink and is basic 4.

The most reactive metal in group three

What are the similarities between low mass stars and high mass stars

The atomic number of calcium (Ca) is 20, and it's mass number is 40. What is true about the subatomic particles that make up a neutral atom of calcium? A) It has 20 protons, 20 neutrons and 20 electrons.

Explain why a sidewalk has built-in cracks every few feet?

How many periods does the periodic table have? 7 18 9 8

Which one is correct A. It allowed them to escape B. It allowed them to chase down C. It allowed them to reach food D. All of these