CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
In an inventory audit, four containers are found to hold the following pure samples. The stated masses have an experimental uncertainty of ±0.1 g.
• 12.0 g of magnesium chloride, MgCl₂ (s)
• 27.0 g of aluminum metal, Al (s)
• 63.5 g of copper metal, Cu (s)
• 98.0 g of sulfuric acid, H₂SO₄ (l)
No additional information is available.
(a) Without carrying out full detailed calculations, predict the order of the four samples from the greatest to the fewest number of chemical entities (atoms or molecules, as appropriate). State any simple ratios or estimates you use.
(b) Provide a written justification for the ranking in part (a), making explicit reference to relative molar masses and the mass of each sample.
(c) Considering the stated ±0.1 g uncertainty, determine whether that uncertainty could change the ranking between the two samples you predicted to have the most entities. Support your conclusion quantitatively.