1. Calculate the number of moles of sulfuric acid that is contained in 250 mL of 8.500 M sulfuric acid solution

2. 7.300 moles of sodium nitrite are needed for a reaction. The solution is 5.450 M. How many mL are needed?

3. What mass (in g) of NH3 must be dissolved in 875 g of methanol to make a 0.430 molal solution?

4. Calculate the molality of a solution that is prepared by mixing 259.5 mL of CH3OH
(d = 0.792 g/mL) and 1387 mL of CH3CH2CH2OH (d = 0.811 g/mL)

5. A solution is prepared by dissolving 318.6 g sucrose (C12H22O11) in 4905 g of water. Determine the molarity of the solution

1.    2.125 moles

2.   1,339.45 mL

3.   6.1079 grams

4.   5.7026 M

5.   0.1898 mol/L

Explanation:

1. Molarity is defined as the number of moles of a substance per litre solution.

-Given the volume of the solution is 250 mL and 8.5 M of sulfuric acid, the moles is obtained as:

Hence, there are 2.125 moles of sulfuric acid in the solution.

2. Given 7.3 moles of sodium nitrate in a solution whose concentration is 5.45M.

#We apply the molarity formula to determine the solution's volume:

Hence, the volume of the solution is 1,339.45 mL

3. Given the mass of the solvent, methanol is 875 g and the molality of the solution is 0.430 m

#we apply the molality formula to calculate the mass of the solute :

Hence, the mass of the solute is 6.4079 grams

4. Given the densities as

We apply the molality formula to find the molality of the solution as follows:

Hence, the molality of the solution is 5.7026 M

5. Molarity is defined as the number of moles of a solute in a 1000 ml of a solution:

Hence, the molality of the solution is 0.1898 mol/L

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.