It is about 6 x 10^23. So in 5 moles of oxygen gas, which has a mass of 5x16=80 grams, there are 5x6x10^23 = 30x10^23 molecules.
When a catalyst is involved in the collisionbetween the reactant molecules, less energy is required for the chemicalchange to take place, and hence more collisions have sufficient energy for reaction to occur. The reaction rate therefore increases. Collision theory is closely related to chemical kinetics
It changes because when the 2 tectonic plates collide they form mountains and volcanoes.
Continental drift causes tectonic plates to either "pull apart" or "crash" into each other.
Plates that crash into each other either form mountains, or when one slides under the other (a subduction zone) volcanoes from.
N(C): N(H)=n(C): n(H)=6: 10
3×10²¹: x=6: 10
x=5×10²¹
Answer:
Elemental gold to have a Face-centered cubic structure.
Explanation:
From the information given:
Radius of gold = 144 pm
Its density = 19.32 g/cm³
Assuming the structure is a face-centered cubic structure, we can determine the density of the crystal by using the following:


a = 407 pm
In a unit cell, Volume (V) = a³
V = (407 pm)³
V = 6.74 × 10⁷ pm³
V = 6.74 × 10⁻²³ cm³
Recall that:
Net no. of an atom in an FCC unit cell = 4
Thus;


density d = 19.41 g/cm³
Similarly; For a body-centered cubic structure

where;
r = 144


a = 332.56 pm
In a unit cell, Volume V = a³
V = (332.56 pm)³
V = 3.68 × 10⁷ pm³
V 3.68 × 10⁻²³ cm³
Recall that:
Net no. of atoms in BCC cell = 2
∴


density =17.78 g/cm³
From the two calculate densities, we will realize that the density in the face-centered cubic structure is closer to the given density.
This makes the elemental gold to have a Face-centered cubic structure.