Answer: 3.024 g grams of hydrogen are needed to convert 76 grams of chromium(III) oxide, 
Explanation:
The reaction equation for given reaction is as follows.

Here, 1 mole of
reacts with 3 moles of
.
As mass of chromium (III) oxide is given as 76 g and molar mass of chromium (III) oxide
is 152 g/mol.
Number of moles is the mass of substance divided by its molar mass. So, moles of
is calculated as follows.

Now, moles of
.given by 0.5 mol of
is calculated as follows.

As molar mass of
is 2.016 g/mol. Therefore, mass of
is calculated as follows.

Thus, we can conclude that 3.024 g grams of hydrogen are needed to convert 76 grams of chromium(III) oxide,
.
The kinetic energy and the physical state of water depend strongly on the temperature;
- Firstly, The kinetic energy of water on a hot stove is higher than that on the counter in the freezer; that the kinetic energy is directly proportional to the temperature according to the relation:
; where R is the universal gas constant, T is the temperature and NA is Avogadro number.
As the temperature increases, the speed of colliding molecules increases and the kinetic energy increases.
- Secondly, The physical state of water depends on the temperature; water has three states (gas, liquid and solid) depends on the temperature.
- If a glass of water is putt on the counter in the freezer, it will be converted to the solid state (ice).
- And, as if it is putt on a hot stove, it will be vapor (gaseous state).
The costs, risks, and benefits to building a nuclear waste storage facility somewhere else
The correct answer is option c, that is, nucleus.
A usual atom comprises three subatomic particles, that is, the neutrons, protons, and electrons. According to Bohr's model, the majority of the mass of an atom is in the nucleus, that is, a small, dense region at the center of each atom, comprising nucleons.
The nucleons incorporate neutrons and protons. All the positive charge of an atom is found in the nucleus and arises from the protons, the neutrons are neutrally-charged, and the electrons are the negatively charged particles found outside of the nucleus.