The missing question is:
<em>What is the percent efficiency of the laser in converting electrical power to light?</em>
The percent efficiency of the laser that consumes 130.0 Watt of electrical power and produces a stream of 2.67 × 10¹⁹ 1017 nm photons per second, is 1.34%.
A particular laser consumes 130.0 Watt (P) of electrical power. The energy input (Ei) in 1 second (t) is:

The laser produced photons with a wavelength (λ) of 1017 nm. We can calculate the energy (E) of each photon using the Planck-Einstein's relation.

where,

The energy of 1 photon is 6.52 × 10⁻²⁰ J. The energy of 2.67 × 10¹⁹ photons (Energy output = Eo) is:

The percent efficiency of the laser is the ratio of the energy output to the energy input, times 100.

The percent efficiency of the laser that consumes 130.0 Watt of electrical power and produces a stream of 2.67 × 10¹⁹ 1017 nm photons per second, is 1.34%.
You can learn more about lasers here: brainly.com/question/4869798
<span>The correct answer is 'freezing point depression'. Colligative properties depend on the concentration of molecules of a solute. Examples of other colligative properties are boiling point elevation or vapour pressure lowering. The salt causes ice on the side walk to melt because it lowers the freezing point. </span>
<h2><em>1. A</em></h2><h2><em>3. B</em></h2><h2><em>4. C</em></h2><h2><em>7. E</em></h2><h2><em>5. F</em></h2>
Two moles of SO2 means 1.204x10^24 molecules, since there are 3 atoms in one molecule, multiply 1.204 x10^24 by 3 and you get 3.612x10^24.