1.Dễ
What colour does blue litmus paper turn in an acid?
- APurple
- BGreen
- CRed
- DBlue (no change)
2.Dễ
Sodium và potassium thuộc nhóm nào?
- AKim loại kiềm thổ (nhóm 2)
- BKhí hiếm (nhóm 18)
- CHalogen (nhóm 17)
- DKim loại kiềm (nhóm 1)
3.Dễ
What is the molar mass of oxygen gas, O₂ (O = 16 g/mol)?
- A48 g/mol
- B8 g/mol
- C32 g/mol
- D16 g/mol
4.Trung bình
Which substance is a non-electrolyte when dissolved in water?
- ASodium chloride
- BPotassium chloride
- CGlucose
- DHydrochloric acid
5.Trung bình
Vinegar contains acetic acid, CH₃COOH. Which functional group makes it an acid?
- AThe methyl group, –CH₃
- BThe amino group, –NH₂
- CThe hydroxyl group of an alcohol, –OH
- DThe carboxyl group, –COOH
6.Trung bình
On an energy diagram, the products are at a lower energy than the reactants. What kind of reaction is shown?
- AEndothermic
- BNuclear
- CReversible only
- DExothermic
7.Khó
Methane burns as CH₄ + 2O₂ → CO₂ + 2H₂O. What mass of CO₂ (44 g/mol) forms from 16 g of CH₄ (16 g/mol)?
- A88 g
- B22 g
- C44 g
- D16 g
8.Khó
Starch and cellulose are both made entirely of glucose units, yet humans can digest starch but not cellulose. Why?
- AThe glucose units are linked differently, and humans lack an enzyme to break cellulose's links
- BCellulose dissolves in water, so it is lost from the gut
- CStarch contains nitrogen, which makes it easier to digest
- DCellulose is really made of amino acids, not glucose, so stomach acid cannot break it
Đáp án
- 1. C · Red
- 2. D · Kim loại kiềm (nhóm 1)
- 3. C · 32 g/mol
- 4. C · Glucose
- 5. D · The carboxyl group, –COOH
- 6. D · Exothermic
- 7. C · 44 g
- 8. A · The glucose units are linked differently, and humans lack an enzyme to break cellulose's links
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