The Equation of reaction
C + O2 === CO2
First Blank spot would be
---- 3.5moles of O2
2nd spot
Up.... 1mole of CO2
Down ---- 2moles of Oxygen atoms
3rd spot
Up... --- 22.4L of CO2(1mole of any gas at STP contains 22.4L)
Down---- 1mole of CO2
Final answer --- 3.5 x 1/2 x 22.4
=39.2L of CO2
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.
Answer:
C₆H₅COOH Benzoic Acid
Explanation:
Here we are using the extraction method to separate benzoic acid from naphtalene in the ether solution by reacting it with the base sodium bicarbonate to produce the salt sodium benzoate ( naphtalene remains in the organic layer ) .
The sodium benzoate is completely soluble in the aqueous layer being a salt, and reacts with hydrochloric acid ( again an acid base reaction ) which precipitates the benzoic acid since the it is insoluble in water hence separating it.
