Why it is advisided to freshly prepare the ferrous sulphate solution for experiment

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

What does x represent in the formula for the compound xcl4?

Ase your answer to this question on the information below. hydrocarbons and fissionable nuclei are among the sources used for the production of energy in the united states. a chemical reaction produces much less energy than a nuclear reaction per mole of reactant. the balanced chemical equation below represents the reaction of one molecule of a hydrocarbon with two molecules of oxygen. chemical equation: ch4 + 2o2 → co2 + 2h2o + 1.48 × 10−18 jthe nuclear equation below represents one of the many possible reactions for one fissionable nucleus. in this equation, x represents a missing product. nuclear equation: write an isotopic notation for the missing product represented by x in the nuclear equation.