Answer:
The bond angle in H2O is about (104.5∘). In H2O,O-atom has two lone pairs.
Explanation:
The VSEPR theory describes five main shapes of simple molecules: linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral.
Answer:

Explanation:
Hello!
In this case, since the combustion of the hamburger released 335.4 kcal of energy and that energy is received by the calorimeter, we can write:

And the heat of the calorimeter is written in terms of the temperature change and the calorimeter constant:

Thus, given the released heat by the hamburger due to its combustion and the temperature change, Cv for the calorimeter turns out:

Best regards!
To answer the question "What is amplitude?", first look at the context of the question. A poem is also given before the questions which discusses about sound waves. Therefore, considering the context above, amplitude is the height of the wave.
Answer:
Energy is absorbed, and an emission line is produced.
Explanation:
Electrons are present and revolving continuously in the orbits that are present around the nucleus. The energy of electron are fixed and unable to move to other orbits due to the strong attractive force of the proton which is present in the nucleus of the atom. If the electron wants to jump from the first energy level to the second energy level, so the electron has to absorb enough energy which can overcome the attractive force of proton.