Chemistry Enthalpy Calculations?

Given the equation:
CaO + H2O ----> Ca(OH)2

A 1 g sample of CaO is dissolved in 100 ml water with density 1.00g/ml. The temperature rise is 3.7 degrees C. The specific heat is 4.00 J/g*deg.

1. Calculate the heat (in J) absorbed/given off by the surroundings when 1 g of CaO is dissolved.
2. Calculate the heat (in kJ) absorbed/given off by the surroundings when 1 mol of CaO is dissolved.
3. What is the molar enthalpy (delta H) for the reaction?

I think I did all my calculations wrong. I got my answers as follows: 1. 1480 J, 2. don't know, 3. 830 kJ/mol

Help please!!!

1. The heat absorbed/given off by the surroundings when 1 g of CaO is dissolved is 1480 J.

2. The heat absorbed/given off by the surroundings when 1 mol of CaO is dissolved is 830 kJ.
3. The molar enthalpy (delta H) for the reaction is 830 kJ/mol.

Don't worry! I'll guide you through the steps of solving these problems.

First, let's tackle question 1.

1. Calculate the heat (in J) absorbed/given off by the surroundings when 1 g of CaO is dissolved.

To calculate the heat absorbed or given off, we need to use the equation:

q = m * c * ΔT

Where:
q = heat absorbed or given off
m = mass of the substance (in this case, 1 g of CaO)
c = specific heat of the substance (given as 4.00 J/g*°C)
ΔT = temperature change in °C (given as 3.7°C)

Plugging in the values:

q = 1 g * 4.00 J/g*°C * 3.7°C
q = 14.8 J

So the heat absorbed or given off by the surroundings when 1 g of CaO is dissolved is 14.8 J.

Now let's move on to question 2.

2. Calculate the heat (in kJ) absorbed/given off by the surroundings when 1 mol of CaO is dissolved.

To calculate the heat in kJ, we need to convert the mass of CaO from grams to moles. The molar mass of CaO (calcium oxide) is 56.08 g/mol.

Given that we have 1 g of CaO, we can calculate the number of moles:

1 g / 56.08 g/mol = 0.0178 mol

Now, we can use the heat calculated in question 1 to calculate the heat for 1 mol:

q/mol = q(given in question 1) / moles

q/mol = 14.8 J / 0.0178 mol
q/mol = 830 J/mol

Since the question asks for the answer in kJ, we divide by 1000 J/kJ:

q/mol = 830 J/mol / 1000 J/kJ
q/mol = 0.83 kJ/mol

So the heat absorbed or given off by the surroundings when 1 mol of CaO is dissolved is 0.83 kJ/mol.

Finally, let's move on to question 3.

3. What is the molar enthalpy (ΔH) for the reaction?

Since we have the amount of heat given off per mole of CaO dissolved, the molar enthalpy (ΔH) can be obtained by equating it to the enthalpy change of the reaction. The coefficient of CaO is 1 in the balanced chemical equation:

CaO + H2O → Ca(OH)2

Therefore, the molar enthalpy (ΔH) is equal to the heat given off per mole of CaO:

ΔH = 0.83 kJ/mol

So the molar enthalpy (ΔH) for the reaction is 0.83 kJ/mol.

I hope this helps! Let me know if you have any further questions.

Sure, I can help you with your calculations!

To calculate the heat absorbed/given off by the surroundings when 1 g of CaO is dissolved (question 1), we need to use the formula:

q = mcΔT

where q is the heat absorbed or given off, m is the mass of the substance, c is the specific heat, and ΔT is the change in temperature.

Given:
mass of CaO = 1 g
specific heat = 4.00 J/g*°C
change in temperature = 3.7 °C

Substituting these values into the formula, we get:
q = (1 g)(4.00 J/g*°C)(3.7 °C)
q = 14.8 J

Therefore, the heat absorbed/given off by the surroundings when 1 g of CaO is dissolved is 14.8 J.

For question 2, to calculate the heat absorbed/given off by the surroundings when 1 mol of CaO is dissolved, we need to use the molar mass of CaO.

The molar mass of CaO is:
Ca: 40.08 g/mol
O: 16.00 g/mol

molar mass of CaO = 40.08 g/mol + 16.00 g/mol = 56.08 g/mol

Now we can convert the mass of CaO from grams to moles:
1 g CaO * (1 mol CaO / 56.08 g CaO) = 0.01782 mol CaO

To calculate the heat absorbed/given off by the surroundings, we multiply this by the heat calculated in question 1:
0.01782 mol CaO * 14.8 J/mol = 0.2632 J

Therefore, the heat absorbed/given off by the surroundings when 1 mol of CaO is dissolved is approximately 0.2632 J.

For question 3, to calculate the molar enthalpy (ΔH) for the reaction, we use the heat absorbed/given off per mole of substance.

To do this, we divide the heat calculated in question 2 by the number of moles of substance:
0.2632 J / 0.01782 mol = 14.75 J/mol

Finally, to convert from joules to kilojoules, divide by 1000:
14.75 J/mol / 1000 = 0.01475 kJ/mol

Therefore, the molar enthalpy (ΔH) for the reaction is approximately 0.01475 kJ/mol.

I hope this helps! Let me know if you have any further questions.