1.Easy
Which group of biological molecules includes fats, oils and cholesterol?
- ANucleic acids
- BProteins
- CCarbohydrates
- DLipids
2.Easy
What are the units of molarity?
- AMoles of solute per kilogram of the solvent used
- BGrams of solute per litre of solution (g/L)
- CGrams of solute per 100 g of solution
- DMoles of solute per litre of solution (mol/L)
3.Easy
What is an electrolyte?
- AA metal that conducts electricity as a solid
- BA gas that dissolves in blood
- CA substance that forms ions and conducts electricity when dissolved in water
- DA substance that dissolves as whole molecules without forming any ions
4.Medium
What is carbon-14 dating used for?
- AEstimating the age of material that was once alive
- BDetecting carbon monoxide in a room
- CFinding the exact age of rocks that are billions of years old
- DMeasuring body temperature
5.Medium
During digestion, large molecules are broken down by adding water across their bonds. What is this reaction called?
- AHydrolysis
- BPolymerisation
- CCombustion
- DCondensation
6.Medium
How does atomic radius change going down a group?
- AIt stays the same
- BIt decreases
- CIt decreases, then increases
- DIt increases
7.Hard
Which statement correctly distinguishes a scientific law from a scientific theory?
- AA theory becomes a law once it is proved
- BLaws apply only to chemistry, theories only to biology
- CA law is only a guess, while a theory is a proven fact
- DA law describes what happens; a theory explains why it happens
8.Hard
Gently heating DNA separates its two strands, but each strand stays in one piece. Why?
- AThe two strands are joined by ionic bonds that melt first
- BHeat converts DNA into a protein
- CEach strand is held together by hydrogen bonds, while the two strands are joined by covalent bonds
- DThe strands are held together by weak hydrogen bonds, while each strand's backbone is covalent
Answer key
- 1. D · Lipids
- 2. D · Moles of solute per litre of solution (mol/L)
- 3. C · A substance that forms ions and conducts electricity when dissolved in water
- 4. A · Estimating the age of material that was once alive
- 5. A · Hydrolysis
- 6. D · It increases
- 7. D · A law describes what happens; a theory explains why it happens
- 8. D · The strands are held together by weak hydrogen bonds, while each strand's backbone is covalent
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