What number should be placed in the blank to balance the equation 4fe + __O2 = 2Fe2O3

Find the empirical formula of a compound that contains 42g of nitrogen and 9g of hydrogen.

How do you get a liquid to a gas?

How many valence electrons are in a stable ion of a period 4 metal?

a gas has a pressure of 1.5 atm, and occupies a volume of 16 L. what will be the new pressure if the volume decreases to 10 L

The energy change, ∆H, associated with the following reaction is + 81 kJ. NBr3 (g) + 3 H2O (g) → 3 HOBr (g) + NH3 (g) What is the expected energy change for the reverse reaction of nine moles of HOBr and two moles of NH3?

What is true of energy as is passes through an ecosystem? a. All of the energy in an organism is used by the animal that eats it. b. Any stored energy in an organism is used by the animal that eats it. c.

Which can associate a suspect and the firing of a gun? (its not b) A) markings on the gun's exterior B) markings on the casing C) markings on the bullet D) powder residues

Which of the following locations would most likely have the most fertile soul?

What is an "alloy" in the chapter of metals in chemistry?

Which one of the atoms shown would be most likely to form a cation with a charge of 1?