A 950.0 mL solution of potassium permanganate was made by dissolving 45.0 g KMnO4 in 750.0 mL of water. Assume water has a density of 1.00 g/mL. (Molar Mass for H = 1 , O = 16 , K= 39 , Mn= 55 ) The mole fraction of the solute =

The correct answer is 6.67×10⁻³.

Explanation:

Based on the given question, the amount of solute (KmNO4) is 45 grams. The molecular weight of KmNO4 is 158 gram per mole. The moles of solute can be determined by using the formula,  

n = mass/molecular weight  

n = 45/158 = 0.28  

The amount of solvent (water) given is 750 milliliters, and the density of water is 1 gm. per ml, 18 gram per mole is the molecular weight of water. So, the moles of solvent will be,  

n = 750/18 = 41.7  

The formula for calculating mole fraction is,  

Mole fraction = mole of solute / (mass of solute + mole of solvent)

The mole fraction of solute can be determined by putting the values in the above mentioned formula,  

Mole fraction of KmNO4 = 0.28/(0.28+41.7)

= 0.28/41.98

= 6.67 × 10⁻³ or 7 × 10⁻³.  

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.

im pretty sure its b