Answer:
1.274.
Explanation:
- Thomas Graham found that, at a constant temperature and pressure the rates of effusion of various gases are inversely proportional to the square root of their masses.
<em>∨ ∝ 1/√M.</em>
where, ∨ is the rate of diffusion of the gas.
M is the molar mass of the gas.
<em>∨₁/∨₂ = √(M₂/M₁)</em>
∨₁ is the rate of effusion of the methane.
∨₂ is the rate of effusion of acetylene gas.
M₁ is the molar mass of methane (M₁ = 16.0 g/mol).
M₂ is the molar mass of acetylene (M₂ = 26.0 g/mol).
<em>∴ The rate of effusion of methane, CH₄, relative to the rate of effusion of acetylene, C₂H₂ = ∨₁/∨₂ = √(M₂/M₁) </em>= √(26.0 g/mol)/(16.0 g/mol) = <em>1.274.</em>
The reaction is that,
1 mole is SiCL4 will produce 1 mole of Si(s) Since there is 1 to 1 relationship then we just multiply the enthalpy of reaction by the number of moles
Enthalpy = -625.5 kJ/mole × 12.5 Moles
= -7,818.75 KJ
= -0.78 ×10⁴KJ
Answer : Option 4) 
Explanation : is the only sample of matter which can be classified as a solution. As the solution can be defined as a liquid mixture which contains a minor component (the solute) that is uniformly distributed within the major component (the solvent).
In this case, the solute is 
which is dissolved in water which acts as an solvent. Also, it has a subscript which is aq. which means aqueous, is often given to the solution in which the solvent is water.
Therefore, is the correct answer.
