A compound being analysed has the percentage composition by mass Ca = 13.9%, W = 63.9%, O = 22.2%. Calculate the empirical formula of this compound

Using rows to represent mathematical operations and a column for each compound we can draw ourselves a table:

                             Ca       W      O
%                         13.9    63.9   22.2
Atomic Mass (Ar) 40       184    16
% / (Ar)                 0.348  0.347 1.43
Ratio                    1    :     1   :   4

This produces the empirical formula Ca1W1Oor more commonly written CaWO4. We retrieve the atomic mass from our periodic table and then divide teh percentage by mass given in the question for each element by its atomic mass. We then take the smallest of these numbers and divide all the other % / (Ar) by it to produce a ratio, it doesn't matter if they aren't exact, they just have to be close to a whole number. This ratio is the ratio of elements in the empirical formula.

HD
Answered by Haydn D. Chemistry tutor

5295 Views

See similar Chemistry GCSE tutors

Related Chemistry GCSE answers

All answers ▸

Why is Chlorine a gas at room temperature but Sodium Chloride is a solid?


Draw a dot and cross diagram of a Chlorine molecule showing the outer electrons only.


Why doesn't the concentration of products or reactants change when a reaction is at dynamic equilibrium?


What is an isotope?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning