The answer is theory because it says if and that means theory
The Doppler effect doesn't just apply to sound. It works with all types of waves, which includes light. Edwin Hubble used the Doppler effect to determine that the universe is expanding. Hubble found that the light from distant galaxies was shifted toward lower frequencies, to the red end of the spectrum. This is known as a red Doppler shift, or a red-shift. If the galaxies were moving toward Hubble, the light would have been blue-shifted.
Physical......................................................
Answer:
This is an example of chemical change because the Kool aid dissolved and turned the water red
1) Find the number of moles that the final solution must contain
M = n / liters of solution => n = M*liters of solution
n = 1.5 mol/liter * 25.0 liter = 37.5 moles
2) Find how many liters of the stock solution contain 37.5 moles of HCL
M = n / liters of sulution => liters of solution = n / M = 37.5 mol / 18.5 mol/liter
liter of solution = 2.03 liter
Answer: 2.03 liter
