Grade 9 Science Review (Part 3)


Question: What does trophic level mean?
Answer: Tropic level refers to feeding level (eg. producer, primary consumer, secondary consumer etc.)

Question: What are nitrates and how are they formed?
Answer: Usable form of nitrogen. Formed by nitrogen fixing bacteria and lightning.

Question: What is an invasive species? How do they affect the ecosystem?
Answer: Invasive species are organisms that successfully establish,and then thrive, in new environments where they did not evolve.
Some effects of invasive species include:
- compete with native species for food, space etc.
- can prey on native species
- can overpopulate as they have no natural predators
- can bring disease

Question: Describe the difference between the four spheres of the Earth.
Answer: Atmosphere - layer of gases surrounding the Earth
Lithosphere - Earth's rocky solid outer layer
Hydrosphere - all water in solid, liquid and gaseous form
Biosphere - zone around Earth where life exists

Question: List the five biomes of Canada. Which biome do you live in?
Answer: Mountain, Tundra, Boreal Forest, Grassland and Temperate Deciduous Forest.
We live in the temperate deciduous forest.


Question: What period and group does barium belong to? How many valence electrons does it have?
Answer: Period 6
Group 2
2 valence electrons

Question: How many atoms in the following chemical equation?
Answer: 7

Question: You perform an experiment in chemistry class. You mix two liquids together and it forms a white solid and many bubbles. What do you call the white solid that was formed? The bell is about to ring for the end of class. You still need to identify the type of gas produced. Which gas test should you try first? Explain why.
Answer: The white solid is called a precipitate.
Try the blazing splint first. If it is hydrogen, it should pop. If it is carbon dioxide, it should go out and if it is oxygen, it might glow brighter. If you don't have time to check with the glowing splint, at least you narrowed down the choices.

Question: Name 5 groups found on the period table and give their location.
Answer: Group 1 - alkali metals
Group 2 - alkaline earth metals
Groups 3-12 - transition metals
Group 17 - halogens
Group 18 - Noble gases

Question: What is electrolysis? Give the word and chemical equation for the electrolysis of water. Draw diagrams of the molecules involved.
Answer: Electrolysis is the use of electricity to separate a compound.
Water yields hydrogen gas and oxygen gas.


Question: A ______________ is the path on which electrons can flow.
Answer: circuit

Question: A circuit is connected with three bulbs in parallel. The total current coming out of the battery is 9 A. How much current is running through the second bulb?
Answer: 3 A

Question: Draw a circuit diagram that contains:
- a 2 cell battery
- 4 resistors (3 in series and 1 in parallel)
- a device to measure current after second resistor
- a device to measure potential difference across the parallel resistor
- a switch to control the whole circuit

Question: Draw a diagram to show how a positively charged rod will attract a neutral object.
What is this process called?
Describe what happens when the objects touch.
Answer: Process of induction.

After the objects touch, electrons will be transferred causing the object to have the same charge. (charging by conduction or contact). The objects will then repel.

Question: You set up a circuit that contains a 9V battery and two lamps connected in series. Each lamp has a resistance of 1.5 ohms. How much current is flowing through the circuit?
Answer: I=V/R
I=9V/1.5+1.5 ohms
There are 3A of current flowing through the circuit.


Question: As our Sun begins to near the end of its lifecycle, it will first form this type of star.
Answer: red giant

Question: What is the difference between apparent and absolute magnitude?
Answer: Apparent magnitude is the brightness of the star as viewed from Earth.
Absolute magnitude is the brightness of star if they were placed 33 ly from Earth.

Question: How do you calculate a distance using triangulation?
Answer: Create a baseline.
Measure the angles from the ends of the baseline pointing towards the object.
Choose a scale and create a scale diagram.
Measure the distance from the object to the baseline at 90 degrees. Convert your measurement to a real life number.

Question: Describe the lifecycle of a very massive star.
Answer: 1. Formed in a nebula
2. Uses nuclear fusion to produce energy
3. Uses up fuel
4. Expands to form a red supergiant
5. Explodes in a supernova
6. Forms a black hole

Question: Sketch a simple H-R diagram. Show the location of our Sun.

For Fun

Question: What does DNA stand for?
Answer: deoxyribonucleic acid

Question: What is the scientific term for your throat?
Answer: pharynx

Question: In your body, which type of cells are the most numerous?
Answer: bacteria

Question: Which organ of your body produces insulin? What is the purpose of insulin.
Answer: Insulin is produced in the pancreas. It plays a role in regulating blood sugar.

Question: What is the largest living organism in the world?
Answer: Honey Mushroom Fungus
It is found in Oregon, USA. It covers 8.4 km and has been growing for 2400 years.