<u>Answer:</u> The mass of sodium chloride solution present is 0.256 grams.
<u>Explanation:</u>
We are given:
39.0 % of sodium in sodium chloride solution
This means that 39.0 grams of sodium is present in 100 grams of sodium chloride solution
Mass of sodium given = 100 mg = 0.1 g (Conversion factor: 1 g = 1000 mg)
Applying unitary method:
If 39 grams of sodium metal is present in 100 grams of sodium chloride solution
So, if 0.1 grams of sodium metal will be present in = of sodium chloride solution.
Hence, the mass of sodium chloride solution present is 0.256 grams.
Kdd was he e shxiuw r thai ed
As long as the equation in question can be expressed as the sum of the three equations with known enthalpy change, its can be determined with the Hess's Law. The key is to find the appropriate coefficient for each of the given equations.
Let the three equations with given be denoted as (1), (2), (3), and the last equation (4). Let , , and be letters such that . This relationship shall hold for all chemicals involved.
There are three unknowns; it would thus take at least three equations to find their values. Species present on both sides of the equation would cancel out. Thus, let coefficients on the reactant side be positive and those on the product side be negative, such that duplicates would cancel out arithmetically. For instance, shall resemble the number of left on the product side when the second equation is directly added to the third. Similarly
Thus
and
Verify this conclusion against a fourth species involved- for instance. Nitrogen isn't present in the net equation. The sum of its coefficient shall, therefore, be zero.
Apply the Hess's Law based on the coefficients to find the enthalpy change of the last equation.
Answer:
Mole fraction of C₄H₄S = 0.55
Explanation:
Mole fraction is moles of solute / Total moles
Total moles are the sum of moles of solute + moles of solvent.
Let's find out the moles of our solute and our solvent.
Mass of solute: 55g
Mass of solvent: 65g
Mol = Mass / molar mass
55 g / 84.06 g/mol = 0.654 moles of C₄H₄S
65 g /123 g/mol = 0.529 moles of C₂H₃BrO
Total moles = 0.654 + 0.529 = 1.183 moles
Mole fraction of thiophene = Moles of tiophene / Total moles
0.654 / 1.183 = 0.55
Answer:
Hailey the answer is D.
Explanation:
if liquid to solid is exothermic then then the other way around would be endorhermic