State symbols: aqueous is a solution, not a pure liquid
Diperkenalkan| English | Makna |
|---|---|
| aqueous solution/ˈeɪkwɪəs səˈluːʃn/ | larutan akueus |
| state symbol/steɪt ˈsɪmbl/ | simbol keadaan |
What would explain this observation?
- NaCl(s) and NaCl(aq) have the same formula but describe different physical forms. The symbol aq means dissolved in water, not a fourth state of pure matter.
Build the model
- Chemical equations use (s) for solid, (l) for liquid, (g) for gas and (aq) for aqueous solution 水溶液.
- Pure water is H₂O(l), while dissolved sodium chloride is NaCl(aq).
- A gas can also dissolve: hydrogen chloride gas is HCl(g), whereas hydrochloric acid solution is HCl(aq).
- The state depends on conditions and the substance’s form, not its formula alone.
- aqueous solution: A solution in which water is the solvent.
- state symbol 状态符号: A label specifying a substance’s physical state or aqueous form in an equation.
Which notation represents sodium chloride dissolved in water?
Kesulitan 1/5 · 100 koin + bonus kecil pada penyelesaian pertama hari ini
(aq) means aqueous - dissolved in water. Sodium chloride solution is written NaCl(aq); (l) would be pure molten salt, which needs heating to about 800 degrees C, and (g) is a gas.
Match each technical term to its precise meaning.
Kesulitan 2/5 · 140 koin + bonus kecil pada penyelesaian pertama hari ini
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- For an aqueous precipitation reaction, AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq) distinguishes the new solid from dissolved substances.
- Magnesium reacting with acid can be written Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g).
- Correct state labels add evidence about the reaction while the coefficients still conserve atoms.
In the lab: Read the stated conditions and observation before labelling: a collected gas, a precipitate, a pure liquid or a solution. Do not infer that every formula containing H is gaseous or that every liquid mixture should be labelled (l). Compare balanced equations with observations from a teacher-approved demonstration and state what each label tells the reader.
Which two habits make the investigation or model in this case more defensible?
Kesulitan 2/5 · 140 koin + bonus kecil pada penyelesaian pertama hari ini
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g) contains one solid species, two aqueous species and one gas species.
- There are four species entries even though the HCl coefficient is two.
- Counting species, atoms and coefficients answers different questions: six Mg atoms correspond to six H₂ molecules in this balanced particle ratio.
Your turn: In Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g), how many distinct species entries are labelled aqueous?
In Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g), how many distinct species entries are labelled aqueous?
Kesulitan 2/5 · 140 koin + bonus kecil pada penyelesaian pertama hari ini
The result is 2 species. Known: Mg(s) + 2HCl(aq) -> MgCl2(aq) + H2(g). Aqueous species: HCl and MgCl2 - 2 species. The coefficient 2 doubles the AMOUNT of HCl, not the number of distinct species.
Check the conclusion and its limits
- Aqueous does not mean the solute has melted.
- A precipitate is solid even while surrounded by liquid.
- State symbols do not change an element symbol or balance a wrong equation.
- A state must be checked against the supplied temperature, pressure and solvent information.
Not true: The symbol aq means a pure substance has become a liquid by melting. (aq) marks a solute dissolved in water - the substance has not melted. Molten sodium chloride is (l); a salt solution at room temperature is always (aq).
- Chemical equations use (s) for solid, (l) for liquid, (g) for gas and (aq) for aqueous solution.
- For an aqueous precipitation reaction, AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq) distinguishes the new solid from dissolved substances.
- Watch for: aqueous does not mean the solute has melted.
The symbol aq means a pure substance has become a liquid by melting.
Kesulitan 1/5 · 100 koin + bonus kecil pada penyelesaian pertama hari ini
(aq) marks a solute dissolved in water - the substance has not melted. Molten sodium chloride is (l); a salt solution at room temperature is always (aq).
A solution in which water is the solvent: write the technical term.
Kesulitan 1/5 · 100 koin + bonus kecil pada penyelesaian pertama hari ini
aqueous solution means A solution in which water is the solvent.