Answer:
The richer source of calcium is fluorite.
Explanation:
Percentage of element in compound :

1. Dolomite is a carbonate of magnesium and calcium:
Given mass of dolomite = 7.81 g
Mass of calcium present in given mass of dolomite = 1.70 g
Percentage of calcium in Dolomite:

2. Fluorite is a mineral of calcium and fluorine:
Given mass of fluorite = 2.76 g
Mass of fluorine present in given mass of fluorite = 1.34 g
Percentage of fluorine in fluorite :

Percentage of calcium in fluorite = 100% - 48.55 % = 51.45%
Percentage of calcium in fluorite > Percentage of calcium in Dolomite
51.455 > 21.77%
So, the richer source of calcium is fluorite.
It is possible to have experiments in which you have multiple variables.
Digestion would be correct. Hope this helps
Answer:
0.643 mol.
Explanation:
- We can use the general law of ideal gas: <em>PV = nRT.</em>
where, P is the pressure of the gas in atm (P = 4.0 atm).
V is the volume of the gas in L (V = 4000 mL = 4.0 L).
n is the no. of moles of the gas in mol (n = ??? mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 30ºC + 273 = 303 K).
<em>∴ n = PV/RT </em>= (4.0 atm)(4.0 L)/(0.0821 L.atm/mol.K)(303 K) = <em>0.643 mol.</em>
This element is Chlorine.
It has 3 energy levels since it is on the third row of the periodic table and it has seven valence electrons since it is in the 17th column (second to last column).