# Universal Gas Constant Lab. Aim: To determine the universal constant for gases by collecting gas from a neutralization reaction and determining the volume and pressure of the gas and then the partial pressure of the gas formed.

Peter Jr Idoko

11 TF

Aim: To determine the universal constant for gases by collecting gas from a neutralization reaction and determining the volume and pressure of the gas and then the partial pressure of the gas formed.

List of Apparatus:

• Ruler ± 0.1cm
• Eudiometer Tube ± 0.05cm3
• Beaker
• Copper wire
• Weighing Balance ± 0.001g

Quantitative Observations:

Volume of HCl(aq) used = 10cm3

Concentration of HCl(aq) used = 3M

Required Mass of Mg(s):

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

P(H20) (at 24C) = 3.0 kPa
P(H2) = Ptotal - PH20

= 107.3-3.0=104.3kPa

Volume of H2(g) = 45cm3 = 0.045dm3

Number of moles of H2(g) = (0.045/24) = 0.001875moles

Ratio of Mg(s) to H2(g) = 1:1

• 0.001875 moles of Mg(s)
• 0.001875 * 24.305 = 0.0455g ≈ 0.04g

Universal Gas Constant: P.V = n.r.T → r = (P.V)/(n.T)

•  R = (104.3 * 0.045)/(0.001875 * (24.5+273)) = 8.41 K-1 mol-1
• Percentage Error = {(8.41-8.31)/8.31} * 100 = 1.2%

Qualitative Observations:

• Colorless gas bubbles observed.
• Concentration swirls observed.
• Significant effervescence noticed close to the magnesium ribbon.
• Colorless gas produced slowly then almost instantaneously the rate at which the colorless gas is being produced speeds up rapidly.
• Eudiometer warms ...