1. Why is it an environmental problem to simply discard wastewater without cleaning it?
- A. Because Earth has a very small and limited supply of usable freshwater.
- B. Because wastewater can be sold to other countries for a high price.
- C. Because dirty water evaporates faster than clean water, affecting weather patterns.
- D. Because it costs too much money to build new pipes to carry it away.
2. If a town's population grows and more factories are built without any water treatment, what is a likely consequence?
- A. The air quality in the town will get better.
- B. There will be more clean water available for drinking.
- C. Local rivers and groundwater will become polluted.
- D. The cost of water for residents will decrease.
3. A farmer uses water mixed with chemicals to grow crops. Why is the runoff from the fields considered wastewater?
- A. It is colder than river water.
- B. It contains harmful substances.
- C. It has already been used by plants.
- D. It will evaporate too quickly.
4. What is the best definition of wastewater?
- A. Water that has been purified for drinking.
- B. Water in its natural state, such as in rivers or lakes.
- C. Water that has been used by humans and now contains harmful substances.
- D. Rainwater that is collected in barrels.
5. Which of the following activities is a common source of wastewater?
- A. Hiking in a forest
- B. Operating a large farm
- C. Watching a rainstorm
- D. Swimming in the ocean
6. Which statement best describes the Law of Conservation of Matter?
- A. Matter can be converted into energy, which is then lost.
- B. The form of matter can change, but its total amount remains constant.
- C. In a chemical reaction, the heaviest substances are always conserved.
- D. Matter is only conserved during physical changes, not chemical changes.
7. A scientist starts with 100 grams of polluted water in a sealed flask. After a treatment process inside the flask, the pollution settles as a solid. What will the total mass of the flask's contents be after the treatment?
- A. Less than 100 grams
- B. Exactly 100 grams
- C. More than 100 grams
- D. It depends on the type of pollutant.
8. If you dissolve 5 grams of salt completely in 200 grams of water in an open beaker, what will be the final mass of the salt-water solution?
- A. 205 grams
- B. 200 grams
- C. 195 grams
- D. Slightly less than 205 grams due to evaporation.
9. Imagine you are trying to prove the Law of Conservation of Matter by boiling water. Which experimental setup would be most effective?
- A. Boiling water in an open pot on a stove.
- B. Weighing a sealed jar of water before and after boiling it.
- C. Comparing the weight of an ice cube to the water it melts into.
- D. Boiling water and collecting all the steam in a balloon to weigh it.
10. When a log burns in a fireplace, it turns into a small pile of ash that weighs much less than the original log. What does the Law of Conservation of Matter tell us about this process?
- A. The process of burning is a rare exception to the Law of Conservation of Matter.
- B. The missing mass was completely destroyed by the intense heat of the fire.
- C. The missing mass was converted into gases like smoke and carbon dioxide that escaped into the air.
- D. The missing mass was converted directly into an equivalent amount of heat and light energy.