Ch. 1 Fundamentals of Chemistry Subchapter – Stoichiometry and Units 1. An element X forms an oxide with the formula X4O10. If 31 g of X combines with 40 g of oxygen, what is the identity of X? A. N B. P C. C D. S Correct Answer: B: P Explanation: We can solve for the atomic mass of X to identify it. The amount in g of X for any amount in g of O is given by: Rearranging the above equation and substituting the given mass of X and O, we get: Thus, the atomic mass of X
When the Mg ribbon was dissolved in HCL solution, the Magnesium Ribbon dissolved forming Hydrogen Gas and Magnesium Chloride. With this information in hand, the value of the Moles of Mg Ribbon can give the value of the moles of H2 gas using stoichiometry since from the equation Mg(s) + 2 HCL (aq) -> MgCl2 (aq) + H2 (g), we see that Magnesium and Hydrogen gas have a one to one ratio so the moles of Magnesium used would be the same as the moles of Hydrogen Gas Produced. The Temperature was also obtained