Answer: 
Explanation: A double displacement reaction is one in which exchange of ions take place.
The compounds which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
Thus the exchange of ions take place and all the compounds are soluble so the chemical formulas are followed by the symbol (aq).
There are only 2 atoms in an Oxygen molecule
Answer:
NH₄Cl, Magnesium sulfate, KCN
Explanation:
Determine whether the given compound name or formula contains a polyatomic ion.
- NH₄Cl. YES. It contains the polyatomic ion ammonium NH₄⁺.
- Magnesium sulfate. YES. It contains the polyatomic ion sulfate SO₄²⁻.
- Sodium phosphide Na₃P. NO.
- Calcium hydroxide Ca(OH)₂. NO.
- KCN. YES. It contains the polyatomic ion cyanide CN⁻.
The correct answer is B. Chewing in the mouth breaks food into small pieces.
Explanation:
In physical changes, substances do not change their chemical composition or properties but only physical features such as this. This occurs during the chewing because the action of chewing only makes food to be broken down in smaller pieces but does not change its identity, composition, or properties. This does not occur once the food is in contact with saliva, the acid in the stomach, etc. because in these cases, the food reacts with other substances and a chemical reaction occurs, which changes food's identity and composition.
Answer:
The student is Incorrect
Explanation:
Even if you break a magnet the poles still remains same. There is no
difference in the magnet Both north and south pole will be there even if you
cut it in to small pieces when you cut it into pieces, if suppose you break 2
magnets and put north and north together it will repel whereas if there are
different poles like north and south it will attract, so even if you break one
single magnet the different poles will attract, Hence the student is incorrect.
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