Fertilisers and sustainability

The ability to perform a chemistry practical safely is a key skill, assessed as part of 16–18 chemistry courses in the UK and Republic of Ireland. This activity gives learners an opportunity to practise these skills, in the context of fertilisers and the sustainability of their manufacture and use.

The practical itself, rates of hydrolysis of urea, and the calculation and conclusion questions are aimed at learners in their second year of a 16­–18 chemistry course. Additional questions on fertiliser sustainability that accompany the practical add context. These could also be used with 14–16 learners. The practical experiment is part of our Challenging plants: fertilisers practicals.

Sustainability in chemistry

This resource accompanies the Education in Chemistry article Link global food security to your lessons on fertilisers where you will find more support and suggestions for how to connect your current chemistry teaching with UN sustainable development goal 2: end hunger, achieve food security and improved nutrition, and promote sustainable agriculture. Link directly to the goal to give this activity an engaging and relevant context.

Teacher notes

The full set of resources to support this practical investigation comprises:

For the practical investigation

• Student sheet containing instructions for completing a practical on the rate of hydrolysis of urea.
• Teacher and technician sheet with some information about the background chemistry and equipment list.

To assess practical skills and add context

• Teacher notes with guidance for each part of the experiment and answers to the questions in the student worksheet.
• Student worksheet with additional questions based on the practical to help with assessment of practical skills and additional green chemistry questions, linking fertiliser to UN sustainable development goal 2.
• Grid for assessing the practical using CPACs (suitable for those following English curriculums).

Learning objectives

• Design an experiment to collect data to measure the rate of hydrolysis of urea.
• Carry out, analyse and conclude using gathered data, for an experiment to measure the rate of hydrolysis of urea.
• Use collected experimental data to identify the initial rate of hydrolysis of urea, find the order of reaction, write a rate equation and identify a rate determining step.
• Use a mathematical model for describing rates of reaction and use a graph to find half-life.
• Expand on the use of fertilisers linking to UN sustainable development goal 2.

This resource contains suggestions for assessing most of the practical skills for the write-up of a complete investigation. You could decide to just assess part of the practical, in which case the learning objectives and worksheets can be adjusted to give more or less information.

Differentiation

This activity is well suited to all learners, regardless of prior attainment. Some learners may require additional support in terms of further detail or prompts, to develop their practical skills.

The additional questions help learners to link their understanding of fertilisers and sustainability beyond the syllabus.

Link fertilisers to your lessons on global food security and enrich your teaching in this topic area with the UN sustainable development goal 15 (restore and promote sustainable use of terrestrial ecosystems, halt biodiversity loss and halt and reverse land degradation) article in this series.