A0.821 gram sample of pure nh f was treated with 25.0 ml of 1.00 m naoh
and heated to drive off the nh.
a. how many mols of naoh are needed to react with the nh f?

The number of moles of NaOH that are needed to react with the NH₄F is 0.0222 mole

From the question,

We are to determine the number of moles of NaOH that are needed to react with the NH₄F

First, we will write the balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

NH₄F + NaOH → NH₃ + NaF + H₂O

This means,

1 mole of NH₄F is needed to completely react with 1 mole of NaOH

Now, we will determine the number of moles of NH₄F present in the reaction

From the given information

Mass of NH₄F = 0.821g

Using the formula

Molar mass of NH₄F = 37.04 g/mol

∴ Number of moles of NH₄F present =

Number of moles of NH₄F present = 0.022165 mole

Now,

From the balanced chemical equation

1 mole of NH₄F is needed to completely react with 1 mole of NaOH

Then,

0.022165 mole of NH₄F would completely react with 0.022165 mole of NaOH

∴ The number of moles of NaOH needed =  0.022165 mole

The number of moles of NaOH needed ≅ 0.0222 mole

Hence, the number of moles of NaOH that are needed to react with the NH₄F is 0.0222 mole

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Here is the complete question:

A 0.821 gram sample of pure NH₄F was treated with 25.0mL of 1.00 M NaOH and heated to drive off the NH₃. How many mols of NaOH are needed to react with the NH4F?

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.