Answer:
Boron atoms lie in hexagonal aromatic graphite-like layers, with a charge of −1 on each boron atom. Magnesium (II) ions lie between layers Binary metal-boron compounds, the metal borides, contain boron in negative oxidation states. Illustrative is magnesium diboride (MgB 2).
Explanation:
Answer:
1. 35 mg of H₃PO₄
2. 27 mol AlF₃; 82 mol F⁻
3. 300 mL of stock solution.
Explanation:
1. Preparing a solution of known molar concentration
Data:
V = 80 mL
c = 4.5 × 10⁻³ mol·L⁻¹
Calculations:
(a) Moles of H₃PO₄
Molar concentration = moles of solute/litres of solution
c = n/V
n = Vc = 0.080L × (4.5 × 10⁻³ mol/1 L) = 3.60 × 10⁻⁴ mol
(b) Mass of H₃PO₄
moles = mass/molar mass
n = m/MM
m = n × MM = 3.60 × 10⁻⁴ mol × (98 g/1 mol) = 0.035 g = 35 mg
(c) Procedure
Dissolve 35 mg of solid H₃PO₄ in enough water to make 80 mL of solution,
2. Moles of solute.
Data:
V = 4900 mL
c = 5.6 mol·L⁻¹
Calculations:
Moles of AlF₃ = cV = 4.9 L AlF₃ × (5.6 mol AlF₃/1L AlF₃) = 27 mol AlF₃
Moles of F⁻ = 27 mol AlF₃ × (3 mol F⁻/1 mol AlF₃) = 82 mol F⁻.
3. Dilution calculation
Data:
V₁= 750 mL; c₁ = 0.80 mol·L⁻¹
V₂ = ? ; c₂ = 2.0 mol·L⁻¹
Calculation:
V₁c₁ = V₂c₂
V₂ = V₁ × c₁/c₂ = 750 mL × (0.80/2.0) = 300 mL
Procedure:
Measure out 300 mL of stock solution. Then add 500 mL of water.
4 moles
64 grams of oxygen contains 4 moles
I think the correct answer would be minerals form. Crystallization is the process of forming crystals from solutions and is one way that minerals are formed in the nature. It is a solid-liquid type of separation. Hope this answers the question. Have a nice day.
Mass of the <span>solvent (H2O) in kg
D = m / V
1.02 = m / 125
m = 1.02 x 125
m = 127.5 g of H2O
127.5 / 1000 => 0.1275 kg
mass of solute in mg:
1000 x ( 1.86 x 10</span>⁻⁵ ) = 0.0186 mg
<span>
ppm = mass of solute in mg / mass of solvent in kg
ppm = 0.0186 / </span><span>0.1275
</span><span>
= 0.1458 ppm
hope this helps!
</span>
