Seth learned in school that iron reacts with oxygen in the air to form iron oxide. The chemical equation is: Fe + O2 à FeO2
Seth wanted to see if this would really happen, so he put 13 grams of tiny iron (Fe) pieces on the window sill outside his house. After two weeks, he saw that the iron no longer looked shiny. He checked the mass of the pieces and saw that it went from 13 to 21 grams. Seth’s friend said this shows that matter is not conserved.

Do you agree or disagree with Seth’s friend? Write a scientific explanation to support your position.

Nitrogen (n), phosphorus (p), and potassium (k) are the main nutrients in plant fertilizers. according to an industry convention, the numbers on the label refer to the mass percents of n, p2o5, and k2o, in that order. calculate the n: p: k ratio of a 30: 10: 10 fertilizer in terms of moles of each element, and express it as x: y: 1.0.

Select the correct answer. which phrase correctly describes temperature? o a. average rotational kinetic energy of the particles in an object o b. average energy of the particles in an object c. average translational kinetic energy of the particles in an object od. all energy possessed by the particles in an object

The atomic radius of sodium is 186 pm and of chlorine is 100 pm. the ionic radius for na+ is 102 pm and for cl– is 181 pm. in going from na to cl in period 3, why does the atomic radius decrease while the ionic radius increases? a. the inner electrons in the sodium cation shield its valence electrons more effectively than the inner electrons in the chloride anion do. b. the inner electrons shield the valence electrons more effectively in the chlorine atom than in the chloride anion. c. the outermost electrons in chloride experience a smaller effective nuclear charge than those in the sodium cation do. d. the outermost electrons in chloride experience a larger effective nuclear charge than those in the sodium cation do. e. monatomic ions are bigger than the atoms from which they are formed.