Ask Question
9 September, 13:39

How many liters of h2 gas, collected over water at an atmospheric pressure of 752 mmhg and a temperature of 21.0°c, can be made from 1.566 g of zn and excess hcl? the partial pressure of water vapor is 18.65 mmhg at 21.0°c?

+4
Answers (2)
  1. 9 September, 15:21
    0
    Answer: 0.299 liter

    Explanation:

    1) Balanced chemical equation

    Zn (s) + 2HCl (aq) → ZnCl₂ (aq) + H₂ (g) ↑

    2) Mole ratios

    1 mol Zn (s) : 2 mol HCl (aq) : 1mol ZnCl₂ (aq) : 2 mol H₂ (g)

    3) Convert 1.566 g Zn into number of moles (n)

    n = 1.566g / 65.39 g/mol = 0.02395 mol

    4) Set the proportion

    1 mol Zn / 2 mol H₂ = 0.02395 mol Zn / x ⇒ x = 0.01197 mol H₂

    5) Calcualte the partial pressure of H₂

    Partial pressure H₂ = Total pressure - partial pressure of water vapor

    Partial pressure H₂ = 752 mmHg - 18.65 mmHg = 733.35 mmHg

    Convert to atm = 733.5 mmHg * 1 atm / 760mmHg = 0.9649 atm

    6) Calculate volume using ideal gas equation

    PV = nRT ⇒ V = nRT/P

    ⇒ V = 0.01197 mol * 0.0821 atm*liter / k*mol * (21 + 273k) / 0.9649atm

    V = 0.2994 liter
  2. 9 September, 16:12
    0
    The answer is V = 0.6 L

    The explanation:

    1 - First we will get P (H):

    p (H) = p total - p (H2O)

    = 752 mmHg - 18.65 mmHg

    = 733 mmHg

    = 733 mmHg X (1 atm / 760 atm) = 0.964 atm

    2 - then when the reaction equation is:

    Zn (s) + 2HCl (aq) - > H2 (g) + ZnCl2 (aq)

    so, then 1 mole of Zn will produce 1 mole of H2.

    so, we need to get first the mole of Zn:

    mole Zn = mass / molar mass

    = 1.566g / 65.38g/mol

    = 0.02395mol

    ∴ 0.02395 mol of Zn will produce 0.02395 mol of H2

    by using the ideal gas equation we can get the volume V:

    when:

    PV = nRT

    when T is the temperature = 21 + 273 = 294 K

    and R is the ideal gas constant = 0.0821 L atm / K mol

    and n is the number of moles = 0.2395 mol

    and P is the pressure = 0.964 atm

    so, by substitution:

    V = (0.02395 moles H2) (0.0821 L atm / K mole) (294 K) / (0.964 atm)

    = 0.6 L
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “How many liters of h2 gas, collected over water at an atmospheric pressure of 752 mmhg and a temperature of 21.0°c, can be made from 1.566 ...” in 📙 Chemistry if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers