A 0.1375-g sample of magnesium is burned in a constant volume calorimeter tha has a heat capacity of 3024 J/C. the temperature increases by 1.126 C. calculate the heat given off by the burning Mg in kJ/g and kJ/mol
q = 3024 x delta T.
kJ/g = 1000*q/0.1375
kJ/g x (24.32 g Mg/mol Mg) = kJ/mol.
To calculate the heat given off by the burning Mg in kJ/g, we need to use the formula:
Heat = (Temperature change) x (Heat capacity)
First, let's convert the mass of Mg from grams to kilograms:
Mass of Mg = 0.1375 g = 0.1375 g / 1000 g/kg = 0.0001375 kg
Now we can calculate the heat given off by the burning Mg in kJ/g:
Heat = (Temperature change) x (Heat capacity)
= 1.126 C x 3024 J/C
= 3403.424 J
To convert Joules to kilojoules, divide the value by 1000:
Heat = 3403.424 J / 1000 kJ/J
= 3.403424 kJ
Now, to calculate the heat given off by the burning Mg in kJ/mol, we need to use the molar mass of magnesium. The molar mass of magnesium (Mg) is 24.31 g/mol.
Using this information, we can calculate the mols of Mg:
Moles of Mg = Mass of Mg / Molar mass of Mg
= 0.1375 g / 24.31 g/mol
= 0.005655 mol
To find the heat given off by the burning Mg in kJ/mol, divide the heat calculated earlier by the number of moles:
Heat/mol = Heat / Moles of Mg
= 3.403424 kJ / 0.005655 mol
≈ 600.634 kJ/mol
Therefore, the heat given off by the burning Mg is approximately 3.403 kJ/g and 600.634 kJ/mol.
To calculate the heat given off by the burning magnesium in kJ/g and kJ/mol, we need to use the equation:
Heat (q) = mass (m) x specific heat capacity (c) x change in temperature (∆T)
First, let's calculate the heat given off by the burning magnesium in kJ/g.
We are given:
- Mass of magnesium (m) = 0.1375 g
- Change in temperature (∆T) = 1.126 °C
- Specific heat capacity (c) = heat capacity of the calorimeter = 3024 J/°C
Converting the mass of magnesium to kilograms:
Mass of magnesium (m) = 0.1375 g ÷ 1000 = 0.0001375 kg
Converting the change in temperature (∆T) to Kelvin:
Change in temperature (∆T) = 1.126 °C + 273.15 = 274.276 K
Now we can calculate the heat (q) in joules using the equation above:
q = (0.0001375 kg) x (3024 J/°C) x (274.276 K)
q = 10 J (rounded to one decimal place)
To convert the heat from joules to kilojoules, divide it by 1000:
q in kJ = 10 J ÷ 1000 = 0.01 kJ
Therefore, the heat given off by the burning magnesium is 0.01 kJ/g.
Now let's calculate the heat given off by the burning magnesium in kJ/mol.
To calculate the number of moles of magnesium used, we need to know the molar mass of magnesium (Mg). The molar mass of Mg is approximately 24.31 g/mol.
Number of moles of Mg = Mass of magnesium (m) / Molar mass of Mg
Number of moles of Mg = 0.1375 g / 24.31 g/mol
Number of moles of Mg ≈ 0.00565 mol (rounded to five decimal places)
Now, to calculate the heat (q) in kilojoules per mole:
q = Heat (kJ/g) x Mass (g) / Number of moles (mol)
q = 0.01 kJ/g x 0.1375 g / 0.00565 mol
q ≈ 0.243 kJ/mol (rounded to three decimal places)
Therefore, the heat given off by the burning magnesium is approximately 0.243 kJ/mol.