Sonia observed that the two balloons repelled each other. This is because both balloons acquired the same charge when she rubbed them with the piece of wool, and like charges repel each other.
The answer is the 3rd one
The period of any wave is one second. the measure of the wave, in this case 440 Hz, is how many wavelengths per second.
Answer:

Explanation:
We know we will need an equation with masses and molar masses, so let’s gather all the information in one place.
M_r: 58.12 44.01
2C₄H₁₀ + 13O₂ ⟶ 8CO₂ + 10H₂O
m/g: 9.511
1. Moles of C₄H₁₀

2. Moles of CO₂
The molar ratio is 8 mol CO₂:2 mol C₄H₁₀

3. Mass of CO₂

The frequency of a photon of red light with wavelength 4.50 x 10−7m is 6.67 x 1014Hz