A sample of 25.0cm³ of 0.500mol/dm³ aqueous ammonium nitrate is heated.Calculate the volume of nitrogen formed, measured at room temperature and pressure?
Answers
Answer:
The amount in moles of a solute in a given volume of solution can be calculated if the concentration of the solution is known. The mass of solute can then be calculated.
Rearranging the equation for concentration below:
\[Concentration~in~mol/dm^{3}=\frac{amount~of~solute~in~mol}{volume~in~dm^{3}}\]
Gives:
Amount of solute in mol = concentration in mol/dm3 × volume in dm3
Example
Calculate the amount of sodium hydroxide, NaOH, in 25.0 cm3 of solution of concentration 0.1 mol/dm3.
Converting the volume from cm3 to dm3, 25.0 cm3 = 25.0 ÷ 1000 = 0.025 dm3.
Amount of NaOH in mol = concentration in mol/dm3 × volume in dm3
= 0.1 mol/dm3 × 0.025 dm3
= 0.0025 mol
Calculating masses from concentration and volume
If the amount in mol of a solute in a given volume of solution is known, its mass can also be calculated.
Question
For the example above, calculate the mass of NaOH in 25.0 cm3 of solution. (Mr = 40 g)
Explanation: