Chemistry-only: match emission lines and use calibration data
مُقدَّم| English | المعنى |
|---|---|
| line spectrum/laɪn ˈspektrəm/ | طيف خطي |
| calibration data/ˌkælɪˈbreɪʃn ˈdeɪtə/ | بيانات المعايرة |
What would explain this observation?
- A mixed flame can hide a visible colour, but an instrument separates the emitted light into lines. Comparing line positions with references can reveal more than one metal ion.
Build the model
- In flame emission spectroscopy, the sample is put into a flame and emitted light passes through a spectroscope.
- Its line-spectrum 线状光谱 output is compared with a reference set to identify metal ions in solution.
- The positions of several matching lines support an identity.
- An unknown may contain lines from more than one reference.
- The method can also measure concentration using calibrated signal data for a selected ion under controlled conditions.
- line spectrum: An emission output with distinct line positions compared with supplied references.
- calibration data 校准数据: Measurements from known concentrations used to relate the stated signal to an unknown concentration.
Which evidence supports the identity of a metal ion in the supplied spectrum?
الصعوبة 1/5 · 100 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
Identity comes from the PATTERN of line positions matching a reference - several lines agreeing rule out coincidence. The concentration axis measures amount, and brightness alone identifies nothing.
Match each technical term to its precise meaning.
الصعوبة 2/5 · 140 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Separate line position from signal strength.
- Position supports identity; intensity at a suitable line, compared with known concentrations, supports quantity.
- Use the supplied wavelength scale or reference table, not a memorised list of invented atomic wavelengths.
- The original figure’s reference X/Y positions are explicitly fictional teaching data.
- Check several lines and overlapping signals; one shared line alone can leave alternatives.
- No electron-transition or advanced instrument mechanism is required here.
In the lab: For a supplied calibration, plot the measured reference signal against known concentration and read an unknown within the calibrated range. Use the same sample preparation, instrument conditions and background correction described by the data. Avoid extrapolation beyond the references without evidence. A teacher-approved handheld spectroscope observation can show line structure; it does not by itself supply quantitative concentration calibration or replace the RP7 chemical-test experience.
Which two habits make the investigation or model in this case more defensible?
الصعوبة 2/5 · 140 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
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: fictional reference X has lines at positions 1 and 4, while Y has lines at 2 and 5 on the supplied position scale.
- The unknown shows all four, supporting X and Y.
- Separately, a provided calibration for one selected ion gives signals 20 and 40 at concentrations 2 and 4 $\dfrac{\text{mg}}{\text{L}}$, with linear zero-background relation in that interval.
- Signal 30 therefore gives 3 $\dfrac{\text{mg}}{\text{L}}$.
- These are supplied-model results, not measured atomic wavelengths or a universal intensity law.
Your turn: A supplied linear zero-background calibration has signal 20 at 2 $\dfrac{\text{mg}}{\text{L}}$ and 40 at 4 $\dfrac{\text{mg}}{\text{L}}$. Read concentration for signal 35.
A supplied linear zero-background calibration has signal 20 at 2 mg/L and 40 at 4 mg/L. Read concentration for signal 35.
الصعوبة 2/5 · 140 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
The result is 3.5 mg/L. Known: signal 20 at 2 mg/L and 40 at 4 mg/L, linear through zero. Signal per concentration = 10 per mg/L. At signal 35: concentration = 35/10 = 3.5 mg/L. The calibration line turns the signal into a concentration.
Check the conclusion and its limits
- Do not infer concentration from the horizontal line position, or identify a spectrum by total brightness alone.
- A matching line pattern supports identity only within the supplied references and resolution.
- Record uncertain or unexplained lines.
- The current section limits interpretation to flame emission with appropriate reference data; it does not demand an advanced mass-spectrum or infrared-spectrum course.
Not true: Emission-line position alone determines an unknown solution’s concentration. Line POSITION identifies the element; line INTENSITY against a calibration measures the concentration. The two axes answer different questions - position never gives amount.
- In flame emission spectroscopy, the sample is put into a flame and emitted light passes through a spectroscope.
- Separate line position from signal strength.
- Watch for: do not infer concentration from the horizontal line position, or identify a spectrum by total brightness alone.
Line POSITION identifies the element; line INTENSITY against a calibration measures the concentration.
الصعوبة 1/5 · 100 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
True. Line POSITION identifies the element; line INTENSITY against a calibration measures the concentration. The two axes answer different questions - position never gives amount.
An emission output with distinct line positions compared with supplied references: write the technical term.
الصعوبة 1/5 · 100 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
line spectrum means An emission output with distinct line positions compared with supplied references.