[{"data":1,"prerenderedAt":106},["ShallowReactive",2],{"cheatsheet-the-mole-and-chemical-formulas":3},{"sheet":4},{"sheetSlug":5,"topicSlugs":6,"primaryTopic":7,"title":8,"subtitle":9,"sections":10},"the-mole-and-chemical-formulas",[5],8,"The Mole & Chemical Formulas","Moles, molar mass, Avogadro's number, percent composition, and empirical/molecular formulas.",[11,23,31,39,47,55,73,81,89,98],{"heading":12,"kind":13,"items":14},"What you're counting","rules",[15],{"ref":16,"mode":19,"provenance":20,"text":21,"source_hash":22},{"type":17,"topic":7,"id":18,"field":17},"rule","MCF-R001","transform","original","Molecular compounds: count molecules (H₂O, CO₂). Ionic compounds: count formula units (NaCl). Elements: atoms (Na, Fe) or molecules (H₂, O₂, P₄, S₈).","473a069b737a695a1c15e46527e4bd07c290c12ec77aebf21e061bd240929fad",{"heading":24,"kind":13,"items":25},"Moles of each element",[26],{"ref":27,"mode":19,"provenance":20,"text":29,"source_hash":30},{"type":17,"topic":7,"id":28,"field":17},"MCF-R002","Each subscript = moles of that element per mole of compound. 1 mol Al₂(SO₄)₃ = 2 mol Al, 3 mol S, 12 mol O. Hydrate waters add to the count.","028737a49f25a6bfcf16f86078da48a57da62712c4d2f369f8bd9ad6cff43839",{"heading":32,"kind":13,"items":33},"Molar mass",[34],{"ref":35,"mode":19,"provenance":20,"text":37,"source_hash":38},{"type":17,"topic":7,"id":36,"field":17},"MCF-R003","Sum the atomic masses of every atom in one formula unit (expand parentheses, include hydrate water), in g/mol. Al₂(SO₄)₃ = 2(26.98) + 3(32.06) + 12(16.00) = 342.14 g/mol.","27859399c04ed3121aff48338e39c0b275f0055b14ff14426f3d7a3881bd85f7",{"heading":40,"kind":13,"items":41},"Mass ↔ moles",[42],{"ref":43,"mode":19,"provenance":20,"text":45,"source_hash":46},{"type":17,"topic":7,"id":44,"field":17},"MCF-R004","Mass → moles: × (1 mol / molar mass). Moles → mass: × (molar mass / 1 mol). g/mol cancels; carry units to self-check.","685b041f5d85f75cf5108cd9095655e13b8462eca776799eac326678e5e1b356",{"heading":48,"kind":13,"items":49},"Avogadro's number",[50],{"ref":51,"mode":19,"provenance":20,"text":53,"source_hash":54},{"type":17,"topic":7,"id":52,"field":17},"MCF-R005","Nₐ = 6.022 × 10²³ entities/mol. Moles → particles: × Nₐ. Particles → moles: ÷ Nₐ. Atoms of an element = mol compound × subscript × Nₐ.","b4fbeddd39939078dd8dbad7f78d5ebb4f8c639cc19ab131bcf8cc5d3b731037",{"heading":56,"kind":13,"items":57},"Hydrates",[58,63,68],{"ref":59,"mode":19,"provenance":20,"text":61,"source_hash":62},{"type":17,"topic":7,"id":60,"field":17},"MCF-R006","Use the full hydrate molar mass (including water). 1 mol CuSO₄·5H₂O = 1 mol anhydrous CuSO₄ + 5 mol H₂O.","d5631224b69f454608462d21dbced6f97c849dce73b38faabcbed813f6269a43",{"ref":64,"mode":19,"provenance":20,"text":66,"source_hash":67},{"type":17,"topic":7,"id":65,"field":17},"MCF-R008","Atom count includes the waters: CuSO₄·5H₂O has 9 O (4 + 5) and 10 H (2 × 5).","3b99893c5417f31bb133bef80f32b68e9047b76206354a5a7c5f2282128a5862",{"ref":69,"mode":19,"provenance":20,"text":71,"source_hash":72},{"type":17,"topic":7,"id":70,"field":17},"MCF-R007","Dissociation uses the anhydrous ions only: CuSO₄·5H₂O → Cu²⁺ + SO₄²⁻ + 5H₂O (2 ions, not 7).","9199a4f3245e31b41f4ad0a610645af50ee2565bb884d7a95485f8f249d3f438",{"heading":74,"kind":13,"items":75},"Percent composition",[76],{"ref":77,"mode":19,"provenance":20,"text":79,"source_hash":80},{"type":17,"topic":7,"id":78,"field":17},"MCF-R009","Mass % of X = (atomic mass of X × subscript) / molar mass × 100%. All element percents sum to 100.00% (± 0.05% rounding).","2835a94ed9031861c9f649bf536d30b6df1be5f96ca80bcf20b8804f61895825",{"heading":82,"kind":13,"items":83},"Empirical vs molecular formula",[84],{"ref":85,"mode":19,"provenance":20,"text":87,"source_hash":88},{"type":17,"topic":7,"id":86,"field":17},"MCF-R010","Empirical formula = smallest whole-number atom ratio. Molecular formula = actual atoms = (empirical)ₙ, where n is a positive integer (n = 1 if they match).","3daf9c7e994fe06f6cb620a7919002c93b1fd5a1f1643f88df54a469cae1cdda",{"heading":90,"kind":91,"items":92},"Empirical formula from % or mass","steps",[93],{"ref":94,"mode":19,"provenance":20,"text":96,"source_hash":97},{"type":17,"topic":7,"id":95,"field":17},"MCF-R011","Assume 100 g (so % = g); convert each element to moles; divide all by the smallest; if a ratio isn't near an integer, multiply all by 2 (for .5), 3 (.33/.67), or 4 (.25/.75).","eb57b4a15ce23ba59ea00a2bf5721f2ed74df6a2e10d673d5cc211d5c20a8986",{"heading":99,"kind":91,"items":100},"Combustion analysis",[101],{"ref":102,"mode":19,"provenance":20,"text":104,"source_hash":105},{"type":17,"topic":7,"id":103,"field":17},"MCF-R012","All C → CO₂ (mass C = mol CO₂ × 12.01), all H → H₂O (mass H = 2 × mol H₂O × 1.008). For C-H-O, mass O = sample − C − H (by difference).","480263f4e73683e8595c16fc9ebdfb6a8947d18d924afc7344796e7103da544c",1787246033352]