When 02235g Of Strontium Reacted With 2500 Ml Of 1.168 M HCl

When 02235g Of Strontium Reacted With 2500ml Of 1168 M Hcl 6318g

When 0.2235 g of strontium reacted with 25.00 mL of 1.168 M HCl, 63.18 g of water was displaced by the H₂ gas produced. The temperature in the reaction flask was 27.0°C, and the barometric pressure was 777 Torr. The molar mass of strontium is 87.62 g/mol. Additionally, when the final reaction mixture was titrated with 0.6137 M NaOH, the endpoint was reached when 39.25 mL of base were added. This report addresses calculations covering the volume and moles of gases evolved, reactants involved, and the stoichiometric ratios in the reaction, supported by appropriate chemical principles and equations.

Paper For Above instruction

The reaction between strontium and hydrochloric acid exemplifies a typical single-displacement halide reaction, producing strontium chloride and hydrogen gas:

Sr (s) + 2 HCl (aq) → SrCl₂ (aq) + H₂ (g)

Understanding the dynamics of this reaction involves calculating various parameters such as the volume of hydrogen gas produced, moles of reactants used, and the stoichiometric relationships between them. The following comprehensive calculations demonstrate these aspects rooted in foundational chemical principles and laws, such as the ideal gas law, molarity, and stoichiometry.

1. Calculation of the volume of hydrogen gas collected

Given the displacement of 63.18 grams of water, we first determine the volume of hydrogen gas produced. Using the density of water (d = 0.9965 g/mL), the volume of water displaced is:

V_water = m / d = 63.18 g / 0.9965 g/mL ≈ 63.4 mL

Since the hydrogen gas displaces this water, the volume of hydrogen at the collection temperature and pressure is approximately 63.4 mL. The water vapor pressure at 27.0°C (27.0 Torr) impacts the total pressure exerted by the gas mixture, and in practical terms, the hydrogen's partial pressure is obtained by subtracting water vapor pressure from the barometric pressure:

P_H2 = P_total - P_{water vapor} = 777 Torr - 27.0 Torr = 750 Torr

Converting Torr to atmospheres (1 atm = 760 Torr):

P = 750 Torr / 760 Torr ≈ 0.987 atm

Similarly, the volume in liters (L) is:

V = 63.4 mL = 0.0634 L

2. Moles of hydrogen gas collected

Using the ideal gas law (PV = nRT), where R = 8.21 x 10^-2 (L·atm)/(mol·K), T = 27.0°C = 300.15 K:

n = PV / RT = (0.987 atm)(0.0634 L) / (8.21 x 10^-2)(300.15 K) ≈ 0.00253 mol

3. Moles of HCl used as a reactant

The initial concentration of HCl is 1.168 M, and the volume used is 25.00 mL (0.025 L):

n_HCl = M x V = 1.168 mol/L x 0.025 L = 0.0292 mol

4. Moles of unreacted HCl in the mixture

The titration with NaOH determines the amount of HCl remaining after the reaction. Given that 39.25 mL of 0.6137 M NaOH was needed to neutralize the unreacted HCl, the moles of unreacted HCl are:

n_{unreacted HCl} = M_NaOH x V_NaOH = 0.6137 mol/L x 0.03925 L ≈ 0.02407 mol

5. Moles of HCl reacted with strontium

The initial moles of HCl minus the unreacted moles give the moles reacted:

n_{reacted HCl} = 0.0292 mol - 0.02407 mol ≈ 0.00513 mol

According to the stoichiometry, 2 mol HCl react with 1 mol Sr:

n_Sr = ½ n_{reacted HCl} ≈ 0.002565 mol

6. Moles of strontium used as a reactant

The moles calculated above reflect the amount of strontium that reacted based on the stoichiometric relationship:

n_Sr = 0.002565 mol

This is consistent with the given mass, as the molar mass of strontium is 87.62 g/mol, and the reacted mass is:

Mass = n x molar mass = 0.002565 mol x 87.62 g/mol ≈ 0.2248 g

7. Molar ratio of hydrogen to strontium

The number of moles of hydrogen gas produced (0.00253 mol) divided by the moles of strontium used (about 0.002565 mol) yields:

Ratio = 0.00253 mol / 0.002565 mol ≈ 0.985

This ratio approximates the theoretical mole ratio of 1:1, suggesting near-complete reaction under the experimental conditions.

8. Ratio of moles of gas collected to moles of strontium used

From the previous calculations, the ratio is approximately:

n_H2 / n_Sr ≈ 0.00253 / 0.002565 ≈ 0.987

This confirms that nearly one mole of hydrogen gas is produced per mole of strontium consumed, consistent with the balanced reaction equation.

Conclusion

These calculations demonstrate the quantitative relationship between reactants and products in this reaction, affirming that the amount of hydrogen gas evolved is directly proportional to the amount of strontium reacted, aligning with stoichiometric expectations. Precise measurements and considerations such as water vapor pressure are crucial for accurate gas volume determinations in experimental chemistry, reinforcing the theoretical principles of the ideal gas law and mole relationships.

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