Question

Pestlab questions 1. Knowing what you do about magnesium and oxygen, what type of compound (lonie or covalent) should form between these two elements? If you expect an ionic compound, comment on what ions will be bonding together, and in what ratio you expect based on their charges. Also, if that wasn't the ratio you obtained in your experiment, comment on possible sources of error 2. A student starts with a 3.96 sample of manganese (Mn, molar mass is 54.94 g). After heating it in a crucible in air, she obtains 8.00 g of oxide. What is the empirical formula of the oxide? SHOW ALL WORK. 3. A student starts with a 4.25 g sample of iron (Fe, molar mass is 55.85 g). After heating it in a crucible in air, she obtains 6.08 g of oxide. What is the empirical formula of the oxide? SHOW ALL WORK

Answer 1

Magridaion Mg- 1 222p6 3 0-182232p Oxygen nueds tu eledhons to complet its octed Magnesium can donate tur tlectsons to cemplete its octet Hence n ienic compaund can form betweon these tur lemints Oxyoem cam ei tas elections to toum anion Magnestum can lase tuwo elactsens to loem cation Simce tur electians are imelved 02- Mg2 aund 02 cembin to larmM0 Poodible souuces of earor AContaminatinem nater (contains Ma ions) 9ncomplete cembistion ef Mg metal Pho loas of produet duwing epuiment Competing skaction by niregen gas Mg-- Mg 2F Ratio Mass Mn 3.96g mdss oxide- Maas Mn 8.009-3.469 Sample= 3.469 Mass 0 11 Moles Manganise 0.072 mal 3-46g x 10mal Ma 11 4.049 XImal 0 16 g o 0.252 mel Malar Ratio Moles of Mn Moles &f O O012mal D.2851 O.253 mal MnOu Grpiical formula

3 Mass iron- .259 Mass 0 6.089-H.259 1.83 9 Males Fe-4.253Xmol Fe 55.858 O10839x Imol0 0.076 mol 0.114 mol 0.076 mal 0.61y 0.114mal Bnpirical fosvmula = Fe, O3 Moles Fe Moles 0 Molar Ratio 2