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

Is the reaction of sulfuric acid with magnesium exothermic or endothermic?

How much force would it take to stop a 100-kg football player if he declerates at 20 m/s^2

Given: 2H2O2 → 2H2O + O2 structure of H2O2: H-O-O-H Bond Bond Energy (kJ/mol) O-H 459 O=O 494 O-O 142 Based on the given bond energies, what is the enthalpy change for the chemical reaction? A. - 352 kJ B. - 210 kJ C. - 176 kJ D. - 105 kJ

Ben and Jerry went for a drive. They decided to stop for a snack and have some ice cream. How long did they stop at the store to eat ice cream? A) 1/2 hour B) 1 hour C) 1 1/4 hours D) 1 1/2 hours

Why would you use an insoluble salt to soften water?

What fact shows that baking a chocolate chip cookie is a chemical reaction? The final product tastes and looks different from the original ingredients. All of the ingredients are mixed up in the cookie.

What specifically does STR measure? A) STR length B) the number of repeating units C) distance traveled on electrophoresis gel D) the difference between the number of repeating units between two STRs

The reaction A (g) ⇌ 2 B (g) A (g) ⇌ 2 B (g) has an equilibrium constant of K = 0.010 K = 0.010. What is the equilibrium constant for the reaction B (g) ⇌ 1 2 A (g) ?

A 0.239 gram sample of a gas in a 100-mL flask exerts a pressure of 603 mm Hg at 14 degrees Celsius. What is the gas?

Which of the following is true about a redox reaction? In a redox reaction, an electron is lost by the reducing agent. In a redox reaction an electron is lost by the oxidizing agent.