1:32

1:32 know what is meant by the terms empirical formula and molecular formula

The empirical formula shows the simplest whole-number ratio between atoms/ions in a compound.

The molecular formula shows the actual number of atoms of each type of element in a molecule.

For example, for ethane:

Molecular formula = C₂H₆

Empirical formula = CH₃

Here are some more examples:

Name	Molecular formula	Empirical Formula
pentene	C₅H₁₀	CH₂
butene	C₄H₈	CH₂
glucose	C₆H₁₂O₆	CH₂O
hydrogen peroxide	H₂O₂	HO
propane	C₃H₈	C₃H₈

Notice from the table that several different molecules can have the same empirical formula, which means that it is not possible to deduce the molecular formula from the empirical formula without some additional information. Also notice that sometimes it is not possible to simplify a molecular formula into simpler whole-number ratio, in which case the empirical formula is equal to the molecular formula.

Hydr0Gen2023-01-10T08:29:26+00:00Categories: (e) Chemical formulae, equations and calculations, 1 Principles of chemistry, Edexcel iGCSE Chemistry|Tags: 1:32, Chemistry, Double, GCSE, GCSE_Chemistry_SpecPoint, SpecPoint, Topic: Calculations, Topic: Crude oil to plastics (D), Topic: Key Calculations|

Past paper questions

Spec	Q'stion	Ans	MS
1:32	Jan '13 (1), Q 9 c	Answer	MkS
1:32	Jan '14 (2), Q 3 b	Answer	MkS
1:32	Jan '18 (1), Q 14 d	Answer	MkS
1:32	May '10 (1), Q 11 d	Answer	MkS
1:32	May '10 (2), Q 7 d	Answer	MkS
1:32	May '11 (1), Q 5 c	Answer	MkS
1:32	May '12 (1), Q 10 a i	Answer	MkS
1:32	May '12 (1), Q 10 a ii	Answer	MkS
1:32	May '12 (1), Q 13 a iii	Answer	MkS
1:32	May '13 (1), Q 4 b i	Answer	MkS
1:32	May '13 (1), Q 4 b ii	Answer	MkS

Hydr0Gen2019-05-13T15:24:09+00:00Categories: PastPaperQuestions|Tags: Chemistry, GCSE, otherPost, PastPaperQuestions|