Answer:

Explanation:
1. Take in account the sulfuric acid at STP:

2. Density is expressed as the ratio between the mass and the volume of a substance so:

Solving for m:

3. Replace values:


Answer:
Molar mass of solute: 300g/mol
Explanation:
<em>Vapor pressure of pure benzene: 0.930 atm</em>
<em>Assuming you dissolve 10.0 g of the non-volatile solute in 78.11g of benzene and vapour pressure of solution was found to be 0.900atm</em>
<em />
It is possible to answer this question based on Raoult's law that states vapor pressure of an ideal solution is equal to mole fraction of the solvent multiplied to pressure of pure solvent:

Moles in 78.11g of benzene are:
78.11g benzene × (1mol / 78.11g) = <em>1 mol benzene</em>
Now, mole fraction replacing in Raoult's law is:
0.900atm / 0.930atm = <em>0.9677 = moles solvent / total moles</em>.
As mole of solvent is 1:
0.9677× total moles = 1 mole benzene.
Total moles:
1.033 total moles. Moles of solute are:
1.033 moles - 1.000 moles = <em>0.0333 moles</em>.
As molar mass is the mass of a substance in 1 mole. Molar mass of the solute is:
10.0g / 0.033moles = <em>300g/mol</em>
5H2O2 + 2KMnO4<span>+ 3H2SO4 = 5O2 + 2MnSO4 + 8H2O + K2SO4
0,145 moles of KMnO4----------in--------1000ml
x moles of KMnO4---------------in------------46ml
x = 0,00667 moles of KMnO4
according to the reaction:
2 moles of KMnO4------------------5 moles of H2O2
0,00667 moles of KMnO4----------------x
x = 0,01668 moles of H2O2
0,01668 moles of H2O2---------in-----------50ml
x moles of H2O2--------------------in----------1000ml
<u>x = 0,334 mol/L H2O2</u></span>