DAS C1 Chemistry Revision: Quantitative Chemistry

Chemistry flashcards based on lecture notes focusing on quantitative chemistry, relative atomic mass, moles, percentage yield, and percentage composition by mass.

What is Relative Atomic Mass?

The average mass of an atom compared to the carbon-12 isotope, which has a mass of exactly 12.

What is a Mole of a Substance?

The relative formula mass (RFM) of the substance in grams, or the mass of 6 x 10^23 atoms/molecules/ions.

What calculation is used to determine the number of moles (No. moles)?

Mass / Mr

Why might the actual yield of a reaction be less than the theoretical yield?

Loss of product during separation, side reactions, and the reaction being reversible and not going to completion.

What is the formula for calculating Percentage Yield?

(mass product actually obtained / theoretical mass of product) x 100

What is the formula for calculating Percentage Composition by Mass?

100 x (mass of element / relative formula mass of compound)

When are percentage yield questions most likely to appear?

This is a calculation performed at the end of the process of determining theoretical mass produced.