Science 9 Unit C Section 1.0

Materials which can harm living things and do not occur naturally in the environment are called ...

• Toxic

• Furons

• Phosphates

• Pollutants

Large quantities of carbon dioxide (130 million tonnes each year) are released into the atmosphere by these …

• volcanoes

• earthquakes

• lightning strikes

• nitrogen fixing bacteria

Certain types of bacteria, located in the root nodules of specific types of plants, such as alfalfa, do most of this in the soil …

• decompose

• scavange

• fix nitrogen

• eliminate pollutants

An organism that harms crops, people or structures is considered to be a …

• insect

• parasite

• bacteria

• pest

To avoid waste chemicals dissolving or corroding some items in a sanitary landfill site, this is used …

• gravel and bacteria

• gravel and compacted soil

• plastic liner and compacted clay

• biodegradable liner and pebbles

Fossils fuels are burned in barbecues, homes, vehicles and industrial plants. When this happens large amounts of carbon dioxide and water vapour are produced. The combustion reaction in a barbecue is represented by the following formula …

• C₃H₈ (fuel) + 5O₂ → 3CO₂ + 4H₂O + energy

• CO₂ + 5O₂ → 3CO₂ + 4H₂O + energy

• sunlight + CO₂ + H₂O → + O₂ + glucose

• energy + 5O₂ → 3CO₂ + 4H₂O

Natural gas may contain hydrogen sulfide, a poisonous chemical. If natural gas does not contain hydrogen sulfide it is considered to be …

• harmful

• corrosive

• sour

• sweet

Toothpaste has a pH of 10. Toothpaste is …

• neutral

• a base

• a strong acid

• an acid base indicator

Testing various substances in the lab resulted in the collection of the following data. By using a few drops of universal indicator, the solutions all changed color. Those solutions that changed to a dark blue were identified as …

• weak acids

• weak bases

• strong acids

• strong bases

Acidic lakes are treated with lime (calcium hydroxide) to neutralize them. The compound calcium sulfate is produced. Calcium sulfate is a(n) …

• acid

• base

• salt

• solution