举一反三
- What's right about the general properties of crystal? A: If there are anions in a crystal, there must be cations B: If there are anions in a crystal, there must be cations C: There are not necessarily chemical bonds in molecular crystals D: There must be no covalent bond in the ionic crystal
- Ionic compounds have the following properties except for ________. A: have high melting and boiling points. B: are soluble in water C: can conduct electricity D: shatter easily
- Solid<br/>materials can be classified into the following types ( ) A: Amorphous B: Polycrystalline C: Single<br/>crystal D: Mixed<br/>crystal
- For the differences of magnetic moments of the following cations in strong and weak octahedral crystal field, which difference is the smallest? A: Mn2+ B: Fe2+ C: Co2+ D: Cu2+
- In an ionic solid, positive and negative ions are bound in the lattice by ionic bonding forces.
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The solubility of ionic compounds is associated with the lattice energy, the higher the lattice energy, the more soluble the ionic compound.
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The non-covalent intermolecular forces described in this video behave differently. How are the forces ranked in terms of their energy? A: Van Der Waals > Ionic > Hydrogen bonds B: Ionic > Van Der Waals > Hydrogen bonds C: Ionic > Hydrogen bonds > Van Der Waals D: Hydrogen bonds > Ionic > Van Der Waals
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在Scopus数据库的高级检索中，检索期刊名称中包含"polymer",同时论文题目中含有"crystal"的文献，正确的检索式为： A: SRCTITLE(polymer) and TITLE(crystal) B: SRCTITLE=polymer and TITLE=crystal C: polymer wn journal and crystal wn ti D: polymer/st and crystal/ti
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14．离子键(ionic bond)
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The sequence of reagents used in Gram staining is () A: Safranin solution → iodine solution → alcohol →<br/>crystal violet B: crystal violet → alcohol → iodine solution → Safranin<br/>solution C: Crystal violet → iodine solution → alcohol → Safranin<br/>solution D: Safranin solution → alcohol → crystal violet → iodine<br/>solution E: Safranin solution → crystal violet → iodine solution →<br/>alcohol