Science Inquiry
Identify the independent variable when testing the effect of sunlight on plant growth.
The amount of sunlight the plant receives.
Which of the following household items is an acid: vinegar, soap, or bleach?
Vinegar
Complete the general word equation:
acid + base -> _______ + ________
acid + base -> salt +water
Name the type of acid secreted by cells in the stomach.
Hydrochloric Acid (HCl)
Where is the driest place on Earth?
Antarctica
Parts of Antarctica have had no rain for 2 million years. The Sahara Desert gets about 25 mm of rain per year. Some part of the Atacama Desert have had no rain for 400 years.
Why is it important to keep all other conditions (e.g. soil type, pot size, water) identical when testing the effect of sunlight on plant growth?
To ensure the test is fair and actually testing the effect of sunlight.
A solution has a pH of 1. What colour will this turn in universal indicator?
Red
Name the gas produced when magnesium (Mg) is placed in hydrochloric acid (HCl).
Hydrogen gas
State the primary cause of heartburn.
Acid reflux resulting in stomach acid entering the oesophagus.
Where was baseball invented?
England
Invented in England in 1744, it was introduced to the USA in 1762.
Accuracy refers to how close a measurement is to its true value. What does precision refer to?
Precision refers to how close repeated measurements are to each other.
What type of ion is typically found in a base?
Hydroxide, OH-
Name the gas produced when limestone (Ca2CO3) is placed in sulfuric acid (H2SO4).
Carbon dioxide gas
Name three systems or processes responsible for maintaining the pH balance in blood.
Buffer system
Respiratory system - breathing
Renal system - urination
What is the most dangerous animal that has ever lived?
Mosquitoes
Female mosquitoes are responsible for the deaths of an estimated 45 billion humans.
What is the difference between a random error and a systematic error?
A random error is unpredictable and can fluctuate due to environmental or human factors.
A systematic error is a consistent and repeatable error that is always in the same direction due to equipment or methodology factors.
Describe what would happen to the pH of a strong base (e.g. bleach) if water is added to it.
The pH of the base will decrease towards 7, as the solution will become more dilute.
Describe how you would test whether hydrogen gas is being produced by a reaction in a test tube.
Invert another test tube over the one containing the reactants to catch the gas.
Light a match, lift the top test tube, and place the match near the opening. If H2 is present, you will hear a pop.
How does the respiratory system compensate for metabolic acidosis?
Breathing rate increases to remove more carbon dioxide from the blood.
What animal is the Canary Islands named after?
Dogs
From Latin Insula Canaria. Canary birds are named after the island.
A drug company tests a new cold medicine. They give the medicine to 1000 people and a sugar pill (placebo) to 1000 people. 70% of the medicine group and 70% of the placebo group recover in three days.
What conclusions can be drawn about the new medicine?
The new medicine is not effective, as it shows no advantage over the body's natural healing process.
Describe the difference between a strong acid and a weak acid.
In a strong acid, the ions completely dissociate (break apart) in solution.
In a weak acid, the ions only partially dissociate in solution.
People living in the northern suburbs of Perth often have limescale (calcium carbonate) on their shower screens and other places where water is left to evaporate.
Suggest a regular household substance that you could use to clean the limescale and explain your choice.
Vinegar
The vinegar is an acid, so will neutralise and dissolve the calcium carbonate that makes up limescale, allowing the scale to be wiped away.
Why does the pancreas secrete bicarbonate into the small intestine?
Bicarbonate is a base, so will neutralise any stomach acid that makes it into the small intestine.
What is the best floor of a building to throw a cat from?
Any floor above the 7th.
Cats have a non-fatal terminal velocity, so if they have time can relax, spread out, and parachute to the ground like a squirrel.