Table 1 shows the results of a school investigation into two packaging films. Equal masses of film were placed in separate compost containers containing dam...
Question 1 Report
Table 1 shows the results of a school investigation into two packaging films. Equal masses of film were placed in separate compost containers containing damp soil. The students kept the temperature, amount of water and mass of soil the same in each container. Film A was poly ethene. Film B was a polymer designed to break down more readily after use. Both films were initially solids with a mass of 12.0 g.
| Time in compost / weeks | Mass of film A / g | Mass of film B / g |
|---|---|---|
| 0 | 12.0 | 12.0 |
| 4 | 11.9 | 9.8 |
| 8 | 11.8 | 7.2 |
(a) State one variable that the students controlled in this investigation. [1]
(b) Calculate the percentage decrease in mass of film B after 8 weeks. [2]
(c) Which film has changed least in mass after 8 weeks? [1]
(d) Explain why the mass of poly ethene changes very little in the compost. [2]
(e) Give two environmental problems caused when used poly ethene bags are not collected or recycled. [2]
Answer Details
(a) One controlled variable was the temperature. The amount of water, mass or type of soil, initial film mass, or measurement time were also controlled. [1]
(b)
\[\text{mass decrease}=12.0-7.2=4.8\text{ g}\]
\[\text{percentage decrease}=\frac{4.8}{12.0}\times100=40\%\]
The percentage decrease is 40%. [2]
(c) Film A, poly ethene, changed least in mass: it decreased by only 0.2 g. [1]
(d) Poly ethene is chemically unreactive because of its strong covalent bonds. Microorganisms do not readily break its polymer chains, so it is not biodegradable and its mass changes very little. [2]
(e) Two valid environmental problems are that poly ethene can persist in landfill and that litter can harm animals. It can also block drains or waterways, form microplastics, or require finite crude-oil resources to replace. [2]
Download The App On Google Playstore
Everything you need to excel in your exams
