B its viscosity decreases
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.
Answer:
The length of foil will be 8107.81 cm or 81.7081 m.
Explanation:
Given data:
Width of roll of foil = 302 mm
Height or thickness = 0.018 mm
Density of foil = 2.7 g/cm³
Mass of foil = 1.19 Kg
Length of foil = ?
Solution:
d = m/ v
v = length (l) × width (w) × height (h)
First of we will convert the Kg into gram and mm into cm.
one Kg = 1000 g
1.19 × 1000 = 1190 g
one cm = 10 mm
302 / 10 = 30.2 cm
0.018 / 10 = 0.0018 cm
Now we will put the values in formula:
d = m/ l× h× w
l = m / d × h× w
l = 1190 g / 2.7 g/cm³× 30.2 cm × 0.0018 cm
l = 1190 g/ 0.146772 g/cm
l = 8107.81 cm or 81.7081 m
Convection: the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.
hope that helps :)