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True or false?
Cadmium is in the mixture because they both contain spectral lines at 625nm.

User Narwhal
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2 Answers

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Final answer:

Identifying elements by spectral lines at a specific wavelength, such as 625nm, requires considering the entire spectrum due to the possibility of overlapping lines from different elements. The strength of spectral lines is influenced by various factors, not just elemental abundance.

Step-by-step explanation:

The statement that Cadmium is in the mixture because they both contain spectral lines at 625nm cannot be confirmed as true or false based purely on the presence of a spectral line at a specific wavelength. The emission or absorption lines in an element's spectrum are unique to that element, acting as a fingerprint. However, multiple elements can have lines that appear close together or even at the same wavelength under certain conditions, leading to potential misidentification.

It's important to consider the entire spectrum and all the lines present when identifying elements. For example, calcium shows dominant lines in specific parts of the spectrum and compounds, such as titanium oxide, display bands rather than discrete lines. Additionally, environmental factors like oxygen molecules in Earth's atmosphere can cause absorption lines, unrelated to the composition of the analyzed matter itself.

If you could observe a star with only one spectral line, concluding its composition would not be straightforward. Several factors, such as the resolution of the spectrometer and the presence of similar lines from different elements, must be considered. The assertion that a star or the Sun contains more of one element than another based solely on the strength of the spectral lines is misleading. Strength of spectral lines is influenced not only by abundance but also by factors such as temperature and pressure.

User Aldous
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true

We describe the luminescence spectral properties of CdS nanoparticles with multiphoton excitation. Three types of CdS nanoparticles were examined which were a CdS/dendrimer composite which displays high anisotropy, Cd2+-enriched nanoparticles which display two emission maxima, and polyphosphate-stabilized nanoparticles which display long wavelength emission. Illumination with long wavelengths near 700−790 nm resulted in two-photon excitation. Essentially the same emission spectra and intensity decays were observed with one-photon and two-photon excitation. Comparison with fluorescein indicates the NPs display large two-photon cross sections near 100 GM. The CdS/dendrimer and Cd2+-enriched CdS nanoparticles displayed large anisotropy values with two-photon excitation, substantially larger than with one-photon excitation. It appears that semiconductor nanoparticles are comparable to organic fluorophores which display the same spectral properties with one-photon and two-photon excitation.

User Nitsas
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