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

Boyle's Law states and signifies what.

Which three elements are found in all the organic compounds that living things need. which of these elements are also found in water

Which of the following best describes the velocity of an object? a.) 30m/s b.) 30m east c.) 30m/s east d.) 30m? s^2

A student neutralized 16.4 milliliters of HCl by adding 12.7 milliliters of 0.620 M KOH. What was the molarity of the HCl acid? (1) 0.168 M (3) 0.620 M (2) 0.480 M (4) 0.801 M

A region in which there is a high probability of finding an electron is called a field. true or false

Raising the temperature of a reacting system increases the rate of the reaction, but does NOT increase the a) activation energy b) number of collisions c) fraction of the reacting particles which possess energies greater than the activation energy

If you have 60 grams of MgCl2 in 5 liters of solution, what is the molarity of this solution?

Is evaporation/condensation a physical or chemical change? Explain

Would the two as yet undiscovered elements A+1 and D+2 react?

Ammonium perchlorate is a powerful solid rocket fuel, used in the Space Shuttle boosters. It decomposes into nitrogen gas, chlorine gas, oxygen gas and water vapor, releasing a great deal of energy.