Edexcel IAL Chemistry Units in Calculations

Practise Edexcel IAL Chemistry units in calculations through density, mass and volume problems, including cm3 to dm3 conversions and rounded answers.

Exam points

Use density units in mass-volume calculations, converting dm3 to cm3 before multiplying or dividing.
Report calculated masses or densities with appropriate g, cm3 or g cm-3 units and sensible rounding.

[Maximum number: 1]

Many cars use fuels containing ethanol as well as hydrocarbons. The E numbers of these fuels show the percentage by volume of ethanol in the fuel. For example, an E5 fuel contains 5\% ethanol and 95\% hydrocarbons by volume.

A brand of E10 fuel contains 92.2% hydrocarbons and 7.80% ethanol by mass.

The energy density is the amount of energy released per kg of a fuel burned. The energy densities of the two components of this brand of fuel are shown.

\begin{array}{ll} \text { energy density of hydrocarbons } & =46.5 \mathrm{MJ} \mathrm{~kg}^{-1} \\ \text { energy density of ethanol } & =29.7 \mathrm{MJ} \mathrm{~kg}^{-1} \end{array}

The density of the E 10 fuel is $0.729 \mathrm{~g} \mathrm{~cm}^{-3}$ .

Calculate the mass of $1500 \mathrm{~cm}^{3}$ of the fuel.

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B.0.0—Units in calculations question 1