Answer:
M = 1.18 mol/L
Explanation:
Moles is denoted by given mass divided by the molecular mass ,
Hence ,

n = moles ,
w = given mass ,
m = molecular mass .
From the information of the question ,
w = 78.3 g
As we known ,
molecular mass of
is 189.36 g/mol
m = 189.36 g/mol
moles can be calculated as -

n = 0.413 mol
MOLARITY -
Molarity of a substance , is the number of moles present in a liter of solution .

M = molarity ( unit = mol / L or M )
V = volume of solution in liter ( unit = L ),
n = moles of solute ( unit = mol ),
From the question ,.
V = 350 mL
Since , 1 mL = 10⁻³ L
V = 0.350 L
n = 0.413 mol
Molarity can be calculated as -

M = 1.18 mol/L
<span>The two elements that constitute almost three fourths of the earth's solid surface are oxygen and silicon. Oxygen accounts for 46.6 percent of the Earth's crust, while silicon is 27.7 percent. The next more plentiful element on the Earth's crust is Aluminum.</span>
Answer: D) 1.00 g
Explanation:
According to the Avogadro's law, the volume of gas is directly proportional to the number of moles of gas at same pressure and temperature. That means,

or,

where,
= initial volume of gas = 2.00 L
= final volume of gas = 3.00 L
= initial moles of gas =
= final moles of gas = ?
Now we put all the given values in this formula, we get


Mass of helium =
Thus mass of helium added = (3.00-2.00) g = 1.00 g