Answer: The molality of solution is 0.66 mole/kg
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

where,
n = moles of solute
= weight of solvent in g
moles of
= 
Now put all the given values in the formula of molality, we get

Therefore, the molality of solution is 0.66 mole/kg
B is the correct answer tbh
The mass of NaCl sample has been 24.3 g. Thus, option A is correct.
The heat of fusion has been the amount of heat required to convert 1 mole of substance into solid to liquid state.
The heat required has been given as:

<h3>Computation for the mass of NaCl</h3>
The given solution has heat of fusion, 
The heat required to melt the sample has been, 
Substituting the values for the mass of NaCl

The mass of NaCl sample has been 24.3 g. Thus, option A is correct.
Learn more about heat of fusion, here:
brainly.com/question/87248
A gas made up of atoms escapes through a pinhole 0.225times as fast as gas. Write the chemical formula of the gas.
Answer:
Explanation:
To solve this problem, we must apply Graham's law of diffusion. This law states that "the rate of diffusion or effusion of a gas is inversely proportional to the square root of its molecular mass at constant temperature and pressure".
Mathematically;

r₁ is the rate of diffusion of gas 1
r₂ is the rate of diffusion of gas 2
m₁ is the molar mass of gas 1
m₂ is the molar mass of gas 2
let gas 2 be the given H₂;
molar mass of H₂ = 2 x 1 = 2gmol⁻¹
rate of diffusion is 0.225;
i .e r1/r2 = 0.225
0.225 = √2 / √ m₁
0.225 = 1.414 / √ m₁
√ m₁ = 6.3
m₁ = 6.3² = 39.5g/mol
The gas is likely Argon since argon has similar molecular mass