Besides building teeth and bones, calcium also keeps your blood and muscles moving and helps your nerves send messages from your brain to the rest of your body. Your body can't make calcium, so you need to get it from food or supplements. While you're pregnant, try to get at least 1,000 mg of calcium every day.
Answer:
8 Silicon atom are present in unit cell.
16 oxygen atoms are present unit cell.
Explanation:
Number of atoms in unit cell = Z =?
Density of silica = tex]2.32 g/cm^3[/tex]
Edge length of cubic unit cell = a = 0.700 nm = 
Molar mass of Silica = 
Formula used :
where,
= density
Z = number of atom in unit cell
M = atomic mass
= Avogadro's number
a = edge length of unit cell
On substituting all the given values , we will get the value of 'a'.
1 silicon is 2 oxygen atoms. then 8 silicon atoms will be 16 oxygen atoms.
Answer:
See explanation below
Explanation:
First, you are not providing any data to solve this, so I'm gonna use some that I used a few days ago in the same question. Then, you can go and replace the data you have with the procedure here
The concentration of liquid sodium will be 8.5 MJ of energy, and I will assume that the temperature will not be increased more than 15 °C.
The expression to calculate the amount of energy is:
Q = m * cp * dT
Where: m: moles needed
cp: specific heat of the substance. The cp of liquid sodium reported is 30.8 J/ K mole
Replacing all the data in the above formula, and solving for m we have:
m = Q / cp * dT
dT is the increase of temperature. so 15 ° C is the same change for 15 K.
We also need to know that 1 MJ is 1x10^6 J,
so replacing all data:
m = 8.5 * 1x10^6 J / 30.8 J/K mole * 15 m = 18,398.27 moles
The molar mass of sodium is 22.95 g/mol so the mass is:
mass = 18,398.27 * 22.95 = 422,240.26 g or simply 422 kg rounded.
