Answer:
Gas
Increase the pressure
Explanation:
Let's refer to the attached phase diagram for CO₂ (not to scale).
<em>At -57 °C and 1 atm, carbon dioxide is in which phase?</em>
If we look at the intersection between -57°C and 1 atm, we can see that CO₂ is in the gas phase.
<em>At 10°C and 2 atm carbon dioxide is in the gas phase. From these conditions, how could the gaseous CO₂ be converted into liquid CO₂?</em>
Since at 10°C and 2 atm carbon dioxide is below the triple point, the only way to convert it into liquid is by increasing the pressure (moving up in the vertical direction).
Answer:
a.
Explanation:
At 28 degrees highest line is CaCl2. Answer a.

The emission spectrum of a chemical element or chemical compound is the spectrum of frequencies of electromagnetic radiation emitted due to an atom or molecule making a transition from a high energy state to a lower energy state. The photon energy of the emitted photon is equal to the energy difference between the two states. There are many possible electron transitions for each atom, and each transition has a specific energy difference. This collection of different transitions, leading to different radiated wavelengths, make up an emission spectrum. Each element's emission spectrum is unique. Therefore, spectroscopy can be used to identify elements in matter of unknown composition. Similarly, the emission spectra of molecules can be used in chemical analysis of substances.