Stoichiometry and Chemical Calculations Review

These flashcards cover key concepts and calculations related to stoichiometry and chemical reactions, drawn from lecture notes for exam preparation.

What concept is fundamental to problem-solving in all branches of science?

Recognizing when an answer is reasonable or realistic.

What happens when a balloon contains only hydrogen (H2)?

Makes no appreciable sound; no oxygen means no reaction.

In the balanced reaction 2H2(g) + O2(g) → 2H2O(g), what allows for the loudest bang in a balloon?

A balloon with a 2:1 ratio of H2 to O2 makes the loudest bang.

How many ions are in 2.5 moles of K2SO4?

There are 5 moles of K+ ions in 2.5 moles of K2SO4, since K2SO4 contains 2 K+ ions per formula unit.

What is the observed mass of water evaporating from 18 mL over 24 hours?

6.022x10^23 molecules of water evaporate per second if the density of water is 1.0 g/mL.

What is the molecular weight of glycerol (C3H8O3)?

92.09 g/mol.

What does the molecular formula for gypsum, CaSO4*2H2O, imply?

There should be a 2:1 ratio of H2O molecules to CaSO4.

If a compound is 84.2% C, how much H will be recovered from 300 g?

47.4 g of H will be recovered.

What is the empirical formula for a compound containing 91.33% element X and 8.67% hydrogen?

Element X is likely silicon (Si) when calculated with the given ratios.

In the Haber process N2 + 3H2 → 2NH3, how much H2 is needed to produce 3,300 metric tons of ammonia?

Would need to purchase approximately 583 metric tons of H2 each day.