What is the mass of 5 moles of Fe2O3?

In a periodic table, dots around an elements symbol indicate the number of valence electrons in an atom? True Or False

2. How does the way elements are grouped in the periodic table serve as an advantage to scientists?

Which of the following equations is balanced? 2H2 + O2 → 4H2O 4Na + O2 → 2Na2O Fe2O3 + H2 → 2Fe + 3H2O CH4 + O2 → CO2 + H2O

1: The atomic number of an atom is equivalent to which of the following? A. the number of protons plus the number of neutrons in the nucleus B. the number of electrons outside the nucleus C. the number of protons in the nucleus D.

A molecule of a certain compound contains two nitrogen atoms and four oxygen atoms what is the molecular formula for this compound

Which statement is the best example of pseudoscience? A. J. joined a group that studies phrenology. Kathleen joined a group that studies endangered species. Joe joined a group that studies herbal remedies.

How many grams of sodium nitrate (NaNO2) will dissolve in 100g of water at 20°C?

Caffeine is about 10 times as soluble in hot water as in cold water. A chemist puts a hot-water extract of caffeine into an ice bath, and some caffeine crystallizes. Is the remaining solution saturated, unsaturated, or supersaturated and why?

Students in a science class learn that groundwater is an important source of drinking water for many communities. They construct a model to study how leaking chemicals from a landfill can affect groundwater.

Given the energy levels of electrons in a hydrogen atom (table), rank the photons emitted by the following electron transitions from longest to shortest wavelength. n=4 to n=3 n=4 to n=2 n=2 to n=1 n=3 to n=1