Select the equations that are correctly balanced.

H2O + 2O2 → H2O2

Fe2O3 + 3H2 → 2Fe + 3H2O

Al + 3Br2 → AlBr3

CaCO3 → CaO + CO2

What does matter have to do with chemistry? How are forces involved?

For the following reaction, calculate how many moles of NO2 forms when 0.356 moles of the reactant completely reacts. 2 N2O5g→4 NO2g+O2g

When a nonmetal oxide reacts with water, it forms an oxoacid with the same nonmetal oxidation state. Give the name and formula of the oxide used to prepare each of these oxoacids: (a) hypochlorous acid; (b) chlorous acid; (c) chloric acid;

How is E related to a period of elements? 1) E generally increases from right to left. 2) E generally decreases from right to left. 3) E is constant within any given Period.

How much of the rock cycle can be observed directly? How much must be inferred? Think about both how long things take to happen in the cycle as well as where different parts of the cycle occur. Refer to specific parts of the cycle in your answer.

Which statement regarding water is true? Energy must be given off in order to break down the crystal lattice of ice to a liquid. Hydrogen bonds are stronger than covalent bonds. Liquid water is less dense than solid water.

Which of the following elements has the fewest valence electrons?. a. beryllium. b. boron. c. carbon. d. lithium

How many molecules are in 4.50 moles of H2O? A. 450 molecules B. 6.02 x 1023 molecules C. 2.71 x 1024 molecules D. 3.00 molecules

A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. How much calcium is contained in 45.0 g of calcium fluoride

If the mass of a material is 111 grams and the volume of the material is 11 cm3, what would the density of the material be?