Atomic mass silicon = 28.085 u
1 mol Si ---------------- 28.085 g
? ------------------------ 245 g
245 x 1 / 28.085 => 8.72 mol
answer A
Electromagnetism
Theoretically it is a branch of physics that contains two sources. Either electrically charged particles or the behavior between Neutrons and protons etc.
Answer:
The volume of the piece of iron is 5.18dL.
Explanation:
The density (ρ) is equal to the mass (m) divided the volume (V).
If we rearrange it, we have:
To express the volume in dL we will need the following relations:
- 1 dL = 0.1 L
- 1 kg = 10³ g
- 1 cm³ = 1 mL
- 1mL = 10⁻³L
Then,
Finally,
Given that the pressure, temperature and area of effusion is constant, the rate of effusion is inversely proportional to the square root of the molecular mass of the gas.
Mr Oxygen = 32
Mr Argon = 40
Effusion Oxygen = 1/√32
Effusion Argon = 1/√40
Effusion Oxygen / Effusion Argon = √(40) / √(32)
=√(40/32) = √(5/4) = 1.19
Thus, Oxygen will effuse 1.19 times faster than Argon. The second option is correct.
