Moles of gas = 0.123
<h3>Further explanation</h3>
In general, the gas equation can be written

where
P = pressure, atm , N/m²
V = volume, liter
n = number of moles
R = gas constant = 0.082 l.atm / mol K (P= atm, v= liter),or 8,314 J/mol K (P=Pa or N/m2, v= m³)
T = temperature, Kelvin
Volume(V) =2.5 L
Pressure(P) = 1.2 atm
Temperature(T) = 25 + 273=298 K

Answer:The approximate atomic mass of lead is 207.24 amu.
Explanation:
Abundance of isotope (I) = 1.4% = 0.014
Atomic mass of the Isotope (I) = number protons + number of neutrons = 82 + 122 = 204 amu
Abundance of isotope (II) = 22.1 % = 0.221
Atomic mass of the Isotope (II) = number protons + number of neutrons = 82 + 125 = 207 amu
Abundance of isotope (III) = 24.1% = 0.241
Atomic mass of the Isotope (III) = number protons + number of neutrons = 82 + 124 = 206 amu
Abundance of isotope (IV) = 52.4% = 0.524
Atomic mass of the Isotope (IV) = number protons + number of neutrons = 82 + 126 = 208 amu
Average atomic mass of an element =

Average atomic mass of lead =

The approximate atomic mass of lead is 207.24 amu.
two reasons why cryolite is used in the electrolysis of aluminium oxide. The mixture of cryolite and aluminium oxide has a lower melting point than pure aluminium oxide. This means a lower amount of energy is required to establish effective conditions for electrolysis and thus makes it more cost effective.
Give two reasons why cryolite is used in the electrolysis of ...https://www.mytutor.co.uk › answers › GCSE › Chemistry
Answer:
2.93 g/L
Explanation:
We can use the <em>Ideal Gas Law </em>to calculate the density of chlorine.
pV = nRT
n = m/M Substitute for n
pV = (m/M)RT Multiply both sides by M
pVM = mRT Divide both sides by V
pM = (m/V) RT
ρ = m/V Substitute for m/V
pM = ρRT Divide each side by RT
ρ = (pM)/(RT)
===============
p = 1.04 atm
M = 70.91 g/mol
R = 0.082 06 L·atm·K⁻¹mol⁻¹
T = 34 °C = 307.15 K Solve for ρ
===============
ρ = (1.04 × 70.91)/(0.082 06 × 307.15)
ρ = 73.74/25.20
ρ = 2.93 g/L