Daily Super-Hard Tasks
Every day gives 3 super-hard tasks based on the book problem sets. Date key: 2026-05-02.
Today's Set
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[Berezan, Problem 1.35] At STP, a gas mixture contains 0.200 L O₂, 40.0 L NH₃, and 0.500 L N₂. Find total mass of the mixture and mass fractions of all three gases.
Hint: Convert each volume to moles, then to mass; mass fraction = component mass / total mass.
[Eremin & Kuzmenko (2005), Problem 2-39] At what molar ratio He:O₂ will the resulting gas mixture be 2.4 times heavier than helium?
Hint: Set target average molar mass: Mmix = 2.4 * M(He).
[Berezan, Problem 1.42] A CO₂/N₂ gas mixture has CO₂ mass fraction 40%. Find the volume at STP of 40.0 g of this mixture.
Hint: Convert mass fractions to moles per 100 g basis, then scale to 40 g and apply STP molar volume.