1.ง่าย
Which of these is a polyatomic ion?
- ASodium, Na⁺
- BOxide, O²⁻
- CChloride, Cl⁻
- DSulfate, SO₄²⁻
2.ง่าย
หมู่ใดมีแก๊สมีตระกูล เช่น ฮีเลียมและนีออน
- Aหมู่ 1
- Bหมู่ 17
- Cหมู่ 2
- Dหมู่ 18
3.ง่าย
What causes the pressure of a gas in a container?
- AThe weight of the container pressing on the gas inside
- BGas particles sticking to the walls
- CGas particles stopping and pushing outward
- DGas particles colliding with the container walls
4.ปานกลาง
A reaction has ΔH = −890 kJ/mol. What does the negative sign tell you?
- AThe reaction is endothermic
- BThe reaction is exothermic
- CThe reaction needs a catalyst
- DThe reaction is at equilibrium
5.ปานกลาง
Why can a very high fever disrupt the body's chemical reactions?
- AHigh temperatures make every enzyme work faster without any limit
- BHigh temperatures turn enzymes into fats
- CHigh temperatures can change the shape of enzymes so they stop working
- DHigh temperatures remove the water from blood
6.ปานกลาง
ไอออนคลอไรด์มีประจุเท่าใด
- A+7
- B−1
- C−2
- D+1
7.ยาก
How much water must be added to 50 mL of a 10% solution to make a 2% solution?
- A200 mL
- B40 mL
- C250 mL
- D100 mL
8.ยาก
Which approach best reduces a health worker's exposure to ionising radiation?
- AStand closer to the source so the job is finished sooner and exposure is shorter
- BRely only on wearing gloves
- CLimit the time near the source, increase the distance and use shielding
- DWork faster without any shielding
เฉลย
- 1. D · Sulfate, SO₄²⁻
- 2. D · หมู่ 18
- 3. D · Gas particles colliding with the container walls
- 4. B · The reaction is exothermic
- 5. C · High temperatures can change the shape of enzymes so they stop working
- 6. B · −1
- 7. A · 200 mL
- 8. C · Limit the time near the source, increase the distance and use shielding
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