Question

Janelle weighed an unknown substance. It had a mass of 20.609 grams. She exposed the substance to a flame and carefully weighed the substance again. The substance then had a mass of 17.39 grams. Write and solve an equation to determine the amount of mass x the substance lost.

Answer 1

Let:

Wi = Initial weight

Wf = Final weight

x = amount of mass the substance lost

Therefore:

`\begin{gathered} Wi-x=Wf \\ where\colon \\ Wi=20.609 \\ Wf=17.39 \end{gathered}`

solve for x:

`\begin{gathered} x=Wi-Wf \\ x=20.609-17.39 \\ x=3.219g \end{gathered}`