When a chemical reaction occurs, .
a phase change takes place
the physical and chemical properties of the products are different from the reactants
the physical and chemical properties of the reactants are the same as the properties of the products
the compounds can be separated by physical means

Ican determine the molar mass of an element by looking on the under the atomic mass for the element. for example the molar mass of phosphorus is 30.974 grams/mole. avogadro’s number tells me the amount of representative particles in 1 mole of any substance. this means 12.011 gram sample of carbon and a 32.0 gram sample of sulfur have the same number of atoms.

What mass of natural gas (ch4) must you burn to emit 276 kj of heat?

What is the oxidation state of an individual bromine atom in nabro3?