1.ง่าย
What colour does blue litmus paper turn in an acid?
- APurple
- BBlue (no change)
- CRed
- DGreen
2.ง่าย
According to the Arrhenius definition, what does an acid produce in water?
- ASodium ions (Na⁺)
- BHydroxide ions (OH⁻)
- COxide ions (O²⁻)
- DHydrogen ions (H⁺)
3.ง่าย
In a solution, what is the solvent?
- AThe substance that is dissolved, usually present in the smaller amount
- BAny solid that will not dissolve, however long it is stirred
- CThe gas given off when a solid dissolves
- DThe substance that does the dissolving, usually present in the larger amount
4.ปานกลาง
What is the name of the molecular compound CO?
- ACarbon dioxide
- BCarbon oxide
- CMonocarbon oxide
- DCarbon monoxide
5.ปานกลาง
Which measurement has three significant figures?
- A56
- B0.00560
- C0.0056
- D5.0006
6.ปานกลาง
What are London dispersion forces?
- AForces that hold protons together in the nucleus
- BAttractions between a hydrogen atom and a metal ion
- CStrong bonds formed by transferring electrons
- DWeak, temporary attractions caused by shifting electrons in molecules
7.ยาก
A salt is dissolved in water in an insulated cup, and the water temperature falls from 25 °C to 20 °C. Which statement is correct?
- ADissolving is endothermic; the dissolving salt took heat from the water
- BDissolving is endothermic; the water took heat from the salt
- CNo energy change occurred, because the temperature fell
- DDissolving is exothermic; the dissolving salt released heat into the water
8.ยาก
A compound is a gas at room temperature, does not conduct electricity in any state, and is made of two nonmetals. What kind of substance is it most likely?
- AA metal with delocalised electrons
- BA giant covalent network solid
- CA simple molecular (covalent) substance
- DAn ionic compound (a lattice of ions)
เฉลย
- 1. C · Red
- 2. D · Hydrogen ions (H⁺)
- 3. D · The substance that does the dissolving, usually present in the larger amount
- 4. D · Carbon monoxide
- 5. B · 0.00560
- 6. D · Weak, temporary attractions caused by shifting electrons in molecules
- 7. A · Dissolving is endothermic; the dissolving salt took heat from the water
- 8. C · A simple molecular (covalent) substance
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