Carbon is an element.
Carbon dioxide is a compound
air is a mixture
water can be both a compound/mixture depending on the type
You would need 67 if you add 56 and 89 = 145 and how i got 67. i went and subtract 212 and 145 = 67 and hope that answer you want if not well least i try
According to
Graham's Law of Diffusion,"the rates of diffusion of two gases are inversely proportional to the square root of their Molar masses or Densities at the same pressure and temperature".
r₁ / r₂ =

Where,
r₁ = Rate of Helium
r₂ = Rate of Oxygen
M₂ = Molar mass of Oxygen = 32 g/mol
M₁ = Molar mass of Fluorine = 4 g/mol
Putting values,
r₁ / r₂ =

r₁ / r₂ =

r₁ / r₂ =
2.82
Result:
Helium gas effuses
2.82 times faster than Oxygen gas.
The pair of elements that will form an ionic bond are Strontium and Chlorine.