1. How much heat is absorbed when 63.7g H(small 2)O [water](l) at 100 degrees C and 101.3 kPa is converted to steam at 100 degrees C? Express your answer in kJ.
Is there an equation?
2.How much heat (in kJ) is released when 0.677 mol NaOH(s) is dissolved in water? (Steps?)
Thank You.
1. To calculate the amount of heat absorbed when water is converted to steam, we need to consider the heat required for both heating the water to its boiling point and for phase change from liquid to gas.
The equation we can use is:
q = m * ΔHvap
Where:
q = heat absorbed (in Joules)
m = mass of water (in grams)
ΔHvap = heat of vaporization of water (in J/g)
To convert the answer to kJ, we divide the result by 1000, since 1 kJ = 1000 J.
The heat of vaporization of water at 100°C is approximately 40.7 kJ/mol.
We need the molar mass of water (H2O) to convert the mass of water to moles. The molar mass of water is approximately 18.015 g/mol.
1 mol of water consists of 18.015 g, so to find the number of moles (n) in 63.7g of water:
n = m/M = 63.7 g / 18.015 g/mol ≈ 3.53 mol
Now we can calculate the amount of heat absorbed:
q = n * ΔHvap = 3.53 mol * 40.7 kJ/mol = 143.77 kJ
Therefore, approximately 143.77 kJ of heat is absorbed.
2. To calculate the amount of heat released when NaOH is dissolved in water, we need to consider the heat of solution. The equation we can use is:
q = n * ΔHsol
Where:
q = heat released (in Joules)
n = number of moles of NaOH
ΔHsol = heat of solution of NaOH (in J/mol)
The heat of solution of NaOH is approximately -445.1 kJ/mol (this value is negative because heat is released during the process).
We are given 0.677 mol of NaOH.
Now we can calculate the amount of heat released:
q = n * ΔHsol = 0.677 mol * -445.1 kJ/mol = -301.66 kJ
Therefore, approximately 301.66 kJ of heat is released during the dissolution of 0.677 mol of NaOH.
1. To calculate the heat absorbed when water is converted to steam, we need to use the equation:
q = m * ΔH
where:
q is the heat absorbed (in kJ),
m is the mass of water (in grams),
ΔH is the enthalpy of vaporization of water (in kJ/g).
The enthalpy of vaporization of water is known to be approximately 40.7 kJ/g.
First, we need to calculate the mass of water that is being converted to steam. We are given the mass of water, which is 63.7 g.
Next, we calculate the heat absorbed using the equation:
q = m * ΔH
q = 63.7 g * 40.7 kJ/g
Calculating the product gives us the answer in kJ.
2. To calculate the heat released when NaOH is dissolved in water, we need to use the equation:
q = n * ΔH
where:
q is the heat released (in kJ),
n is the number of moles of NaOH,
ΔH is the enthalpy change of solution (in kJ/mol).
We are given n, which is 0.677 mol.
To calculate the heat released, we need to know the enthalpy change of solution of NaOH. The enthalpy change of solution can vary depending on factors such as concentration and temperature, so we need that information to proceed with the calculation.
Once you have the value for ΔH, you can calculate the heat released using the equation:
q = n * ΔH
This will give you the answer in kJ.
1. Yes, there is an equation.
q = mass x delta Hvap. Whether you get calories, J, or kJ depends upon the unit for delta Hvap
2. You don't have enough information to answer this question. You need the heat of solution of 1 mol NaOH.