1.Easy
What does organic chemistry study?
- ACompounds made of metals
- BOnly compounds found in plants
- CCompounds based on carbon
- DOnly the noble gases
2.Easy
What does the rule "like dissolves like" mean?
- AEvery substance dissolves in water
- BSolids dissolve only in other solids
- CPolar solvents dissolve polar substances, and nonpolar solvents dissolve nonpolar ones
- DOnly substances with identical formulas can ever dissolve in each other
3.Easy
What is a beta particle?
- AA wave of visible light
- BA helium nucleus with two protons and two neutrons
- CA neutron that leaves the nucleus
- DA high-energy electron released from a nucleus
4.Medium
Why does ice float on liquid water?
- AIce is less dense than liquid water
- BIce is denser than liquid water
- CIce contains trapped air from the freezer
- DIce has a higher mass than the same volume of water
5.Medium
How does a catalyst speed up a reaction?
- AIt provides a different pathway with a lower activation energy
- BIt adds extra reactant to the mixture
- CIt raises the temperature of the reactants so they move faster
- DIt makes the reaction more exothermic
6.Medium
When a nucleus emits an alpha particle, how do its mass number and atomic number change?
- ANeither changes
- BMass number falls by 2 and atomic number falls by 4
- CMass number falls by 4 and atomic number falls by 2
- DMass number stays the same and atomic number rises by 1
7.Hard
Why is it easier to remove the outer electron from a potassium atom than from a lithium atom?
- APotassium's outer electron is in a full shell
- BPotassium has fewer protons, so its nucleus pulls much more weakly on every electron
- CPotassium's outer electron is farther from the nucleus and more shielded by inner electrons
- DLithium has more electron shells than potassium
8.Hard
Magnesium burns as 2Mg + O₂ → 2MgO. What mass of MgO (40 g/mol) forms from 48 g of Mg (24 g/mol)?
- A40 g
- B80 g
- C48 g
- D160 g
Answer key
- 1. C · Compounds based on carbon
- 2. C · Polar solvents dissolve polar substances, and nonpolar solvents dissolve nonpolar ones
- 3. D · A high-energy electron released from a nucleus
- 4. A · Ice is less dense than liquid water
- 5. A · It provides a different pathway with a lower activation energy
- 6. C · Mass number falls by 4 and atomic number falls by 2
- 7. C · Potassium's outer electron is farther from the nucleus and more shielded by inner electrons
- 8. B · 80 g
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