Calculate the volume of HNO3 that must be introduced in the calorimeter,knowing that it were used 60 ml NaOH, Cc=100cal/grd and delta H=-13,5 kcal/mol.. please help me,i have no clue for this..
To calculate the volume of HNO3 needed, we need to use the equation:
moles of NaOH = moles of HNO3
First, let's find the moles of NaOH:
Given: Volume of NaOH (V) = 60 mL
Molarity of NaOH (M) = ?
To find the molarity (M), we need to know the concentration of NaOH in moles per liter (mol/L).
Now, assuming the concentration of NaOH is given, we can use the formula:
moles of solute = concentration (mol/L) × volume (L)
To convert the volume from milliliters (mL) to liters (L), we divide by 1000:
Volume (L) = 60 mL / 1000 = 0.06 L
Let's assume the concentration of NaOH is 0.1 mol/L (you can adjust this value if you have a different concentration).
Now we can calculate the moles of NaOH:
moles of NaOH = concentration × volume
= 0.1 mol/L × 0.06 L
= 0.006 mol
Since the balanced equation for the reaction between NaOH and HNO3 is:
HNO3 + NaOH → NaNO3 + H2O
We see that the stoichiometric ratio between NaOH and HNO3 is 1:1. This means that for every mole of NaOH used, we need one mole of HNO3.
Therefore, the number of moles of HNO3 needed is also 0.006 mol.
Now, let's calculate the volume of HNO3 needed:
Given: ΔH = -13.5 kcal/mol
Calorimeter constant (Cc) = 100 cal/°C
We can use the equation:
ΔH = q / moles
where q is the heat transfer (in calories).
Since we are given the volume of NaOH and the calorimeter constant, we can find the heat transfer (q):
q = Cc × ΔT × volume
Given: ΔT (change in temperature) is not specified, so let's assume it is 1°C (you can adjust this value if you have a specific value).
q = 100 cal/°C × 1°C × 60 mL
= 6000 cal
Now we substitute the values into the equation:
ΔH = q / moles
-13.5 kcal/mol = 6000 cal / 0.006 mol
Multiplying both sides by -1 to solve for the positive value:
13.5 kcal/mol = 6000 cal / 0.006 mol
Rearranging the equation to solve for the volume of HNO3:
Volume of HNO3 = (6000 cal / 0.006 mol) × (1 kcal/1000 cal)
= (6000/0.006) kcal/mol × (1/1000) L/kcal
= 1,000,000 L/mol
So, based on the given information, you would need 1,000,000 liters of HNO3 to introduce into the calorimeter.