Explain how there can be so many different kinds of suntances in the world

Calculate the number of sulphur atoms in 64g of sulphur

Which of the following materials should be classified as a mixture? Air Carbon Salt Water

Which statement is true if the Delta. Hrxn of a reaction is positive? The reaction is endothermic. The reaction is exothermic. There is more reactant than product. There is more product than reactant.

Calcium metal reacts with water to form calcium hydroxide and hydrogen gas. How much hydrogen is formed when 0.50 g of calcium are added to water?

Number of electrons the atom my accept from another atom? Hydrogen, carbon, nitrogen, oxygen, fluorine

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?