100g water, need to raise solution of sodiun acetate 20 degrees. how much energy does it require and how much sodium acetate will you need? Enthalpy of crystallisation is -260kJ.
How do I work it out?q= Cp n ∆T?
Do you use the density of SA any where? it is 1.528g.
I need the correct calculation to calculate the total enthalpy of the reaction.
To calculate the amount of energy required to raise the temperature of a solution of sodium acetate, you can use the formula:
q = Cp * m * ∆T
where:
q is the total heat energy required (in joules)
Cp is the specific heat capacity of water (4.18 J/g°C)
m is the mass of water (100g)
∆T is the change in temperature (20°C)
Using this formula, you can calculate the energy required:
q = 4.18 J/g°C * 100g * 20°C
= 8360 J
Now, to calculate the amount of sodium acetate required, you need to consider the enthalpy of crystallization. The negative sign indicates that the reaction is exothermic and releases heat.
The enthalpy change (∆H) for sodium acetate's crystallization is given as -260 kJ. To convert kJ to J, you need to multiply it by 1000:
∆H = -260 kJ = -260,000 J
Since the enthalpy change for the reaction is for one mole of sodium acetate, you now need to calculate the number of moles of sodium acetate:
∆H = q * n
where:
q is the energy change (-260,000 J)
n is the number of moles of sodium acetate
Rearranging the equation, you get:
n = ∆H / q
= (-260,000 J) / (8360 J)
= -31.1009
Now, we need to take into account the density of sodium acetate (1.528 g/mL) to calculate the mass of sodium acetate needed.
Since the density is given in grams per milliliter (g/mL), you need to convert the mass of water (100g) to milliliters.
100g of water is equal to 100 mL.
So, if the density of sodium acetate is 1.528 g/mL, the mass of sodium acetate needed is:
mass = volume * density
= 100 mL * 1.528 g/mL
= 152.8 g
Therefore, you would need approximately 152.8 grams of sodium acetate to raise the temperature of the 100g water solution by 20 degrees Celsius.