Answer:
Mole fraction of solute (heptane) → 0.73
Explanation:
Mole fraction = Moles of solute or solvent / Total moles
Let's calculate the moles of everything:
Moles of solute → Mass of solute / Molar mass
36 g / 100 g/mol = 0.36 moles
Moles of solvent → Mass of solvent / Molar mass
16 g / 119.35 g/mol = 0.134 moles
Total moles = 0.36 + 0.134 = 0.494 moles
Mole fraction of solute = 0.36 / 0.494 → 0.73
Answer:
B.) The coefficients give the molar ratio of the reactants.
Explanation:
The coefficients represent how many of each molecule are within a reaction. Coefficients are added to make sure the amounts of each element are the same on both sides of the reaction. You can use the coefficients to convert between moles of each molecule. As such, the best answer is B.) because coefficients are what allow you to construct a mole ratio.
Answer:
The value is 
Explanation:
Generally the reaction between oxygen and magnesium is
Generally from the law of mass conservation in a chemical reaction we have that
Here 
is the mass of magnesium
is the mass of oxygen
is the mass of magnesium oxide
So
=> 
=>
Answer:
ΔE = 5.02 x 10⁻¹⁹ j
Explanation:
ΔE (photon) = h·f = (6.63 x 10⁻³⁴ j·s)(7.57 x 10¹⁴ s⁻¹) = 5.02 x 10⁻¹⁹ j
h = Planck's Constant = 6.63 x 10⁻³⁴ j·s
f = frequency (given) = 7.57 x 10¹⁴ s⁻¹
