R2.1 How much? The amount of chemical changeIB Chemistry HL: Flashcards

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Three steps of a reacting-mass calculation?

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Three steps of a reacting-mass calculation?: Convert to moles, apply the mole ratio, convert to the quantity asked for.
Molar volume of a gas at STP (IB)?: 22.7 dm³ mol⁻¹ at 273 K and 100 kPa.
Formula linking concentration, amount and volume?: c = n ÷ V, with V in dm³.
How do you convert cm³ to dm³?: Divide by 1000.
Define limiting reactant.: The reactant completely used up, which determines the maximum amount of product.
How do you identify the limiting reactant?: Divide the moles of each reactant by its coefficient; the smallest result is limiting.
Does adding more of an excess reactant raise the theoretical yield?: No: it is fixed by the limiting reactant.
Define theoretical yield.: The maximum amount of product calculated from the limiting reactant.
Formula for percentage yield?: Experimental yield ÷ theoretical yield × 100.
Three reasons for a yield below 100%?: Incomplete or reversible reaction, side reactions, losses during transfer and purification.
Formula for atom economy?: M(desired product) ÷ M(all reactants) × 100, using equation coefficients.
Atom economy of an addition reaction with one product?: 100%.
Difference between atom economy and percentage yield?: Atom economy comes from the balanced equation; percentage yield from the amount actually obtained.