When 4 liters of hydrogen gas and 2 liters of oxygen gas react to form water at a constant temperature and pressure, how many liters of water vapor (steam) will be formed? 2H2  +  O2 

The sub-particle that emits a photon in an excited atom is a(n) ______________________.  

An element with the electronic structure 1s22s22p2 is in which group of the periodic table?

A 25.3 cm3 gold sample has a mass of 488 g. What is the density of gold in grams per cm3?

Which one of the following cannot be the chemical symbol for an element?

The correct symbol for an isotope having 12 protons and 14 neutrons is:

Which of the following reactions is not balanced?

The element with the electron arrangement of 2, 8, 6 is:

How many atoms of xenon are in 3.50 moles of Xe gas?

Carbon dioxide, CO2, contains 12.01 g of carbon in every 44.01 g of carbon dioxide. What mass of carbon dioxide can be formed from 85.20 g of carbon?