1.Dễ
What are the units of molarity?
- AMoles of solute per litre of solution (mol/L)
- BGrams of solute per 100 g of solution
- CMoles of solute per kilogram of the solvent used
- DGrams of solute per litre of solution (g/L)
2.Dễ
What is an element?
- AA substance of two or more elements chemically bonded together
- BA particle with an electric charge
- CA substance made of only one kind of atom
- DA physical mixture of different substances
3.Dễ
What is a solution?
- AA mixture that is the same throughout (homogeneous)
- BA solid that has been melted
- CA mixture in which particles settle out on standing
- DA pure compound made of two elements
4.Trung bình
Which element has chemical properties most similar to calcium?
- APotassium
- BMagnesium
- CScandium
- DCarbon
5.Trung bình
What percentage of the mass of water (H₂O, 18 g/mol) is hydrogen (H = 1 g/mol)?
- AAbout 11%
- BAbout 5,6%
- CAbout 89%
- DAbout 67%
6.Trung bình
Nguyên tử oxygen có bao nhiêu electron hóa trị (lớp ngoài cùng)?
- A2
- B6
- C8
- D16
7.Khó
Which phase change absorbs energy from the surroundings (is endothermic)?
- AFreezing
- BSublimation
- CDeposition
- DCondensation
8.Khó
What is a triglyceride made of?
- AOne glycerol molecule joined to three fatty acids
- BOne fatty acid joined to three glycerol molecules
- CThree glucose molecules joined together
- DThree amino acids joined by peptide bonds
Đáp án
- 1. A · Moles of solute per litre of solution (mol/L)
- 2. C · A substance made of only one kind of atom
- 3. A · A mixture that is the same throughout (homogeneous)
- 4. B · Magnesium
- 5. A · About 11%
- 6. B · 6
- 7. B · Sublimation
- 8. A · One glycerol molecule joined to three fatty acids
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