Answer is: mass of sodium nitrate is 21,25 g.
m(H₂O) = 500 g · 1 kg/1000 g = 0,5 kg.
b(solution) = 0,500 m = 0,500 mol/kg.
m(NaNO₃) = ?
b(solution) = n(NaNO₃) ÷ m(H₂O).
n(NaNO₃) = 0,500 mol/kg · 0,5 kg.
n(NaNO₃) = 0,25 mol.
m(NaNO₃) = n(NaNO₃) · M(NaNO₃).
m(NaNO₃) = 0,25 mol · 85 g/mol.
m(NaNO₃) = 21,25 g.
I got b 5)A sample of pure sodium-24 has an initial mass of 10.0 grams. How many grams of sodium-24 will remain at the end of 4 half-lives?
A. 0.315
B. 0.630
C. 5.00
D. 6.00
Answer:
1.81 x 10²⁴ atoms
Explanation:
To find the number of atoms in the given number of moles, we need to understand that every substance contains the Avogadro's number of particles.
More appropriately, a mole of any substance will contain the Avogadro's number of particles which is 6.02 x 10²³ atoms
So;
If 1 mole of a substance = 6.02 x 10²³ atoms;
3 mole of MgCl₂ will contain 3 x 6.02 x 10²³ = 1.81 x 10²⁴ atoms
