A sample of urea contains 1.121 g of N, 0.161 g of H, 0.48 g of C, and 0.64 g of O. What is the empirical formula of urea?

Which element represents 10% of the elements in the human body? a. calcium b. nitrogen c. hydrogen d. oxygen

Which is not a reason that water is used to store spent fuel rods from nuclear power plants? Water increases the speed of the chain reaction in the fuel rods.

What is an electron that occupies the outermost energy level or shell of an atom called?

Which one of the following scenarios accurately describes a condition in which resonance can occur? A.

Describe three examples from sports in which a force changes the velocity of an object or a person.

Identify the spectator ions in the following complete ionic equation. 2k (aq) s2 - (aq) pb2 (aq) 2no-3 (aq) →pbs (s) 2k (aq) 2no-3 (aq) express your answers as ions separated by a comma.

4. A bird left its post and flew in a triangular path. It flew 21 yards south, 72 yards east and 75 yards diagonally to end back at the post. Is it a right triangle?

Condension occurs in the inside of your windows in Winters, why?

How can you use Hess's law to determine a reaction's enthalpy?

7. How much energy in KJ is released when 15.0 g of steam at 100.0 degrees Celsius is condensed and then frozen to ice at 0.0 degrees Celsius?