To find AH°rxn, we use the following equation:
What we're going to do is to sum the enthalpy of the products and then substract with the enthalpy of the reactives:
As you can see, we need to multiply by the coefficients of the reaction.
Now, just replace the values of the table:
So the answer is -822.2kJ/mol.
For b:
Now, just replace the values of the table:
The answer for b is -1036kJ/mol.
Answer: B
Explanation: I answered randomly
Hey there!:
Molar mass of Mg(OH)2 = 58.33 g/mol
number of moles Mg(OH)2 :
moles of Mg(OH)2 = 30.6 / 58.33 => 0.5246 moles
Molar mass of H3PO4 = 97.99 g/mol
number of moles H3PO4:
moles of Mg(OH)2 = 63.6 / 97.99 => 0.649 moles
Balanced chemical equation is:
3 Mg(OH)2 + 2 H3PO4 ---> Mg3(PO4)2 + 6 H2O
3 mol of Mg(OH)2 reacts with 2 mol of H3PO4 ,for 0.5246 moles of Mg(OH)2, 0.3498 moles of H3PO4 is required , but we have 0.649 moles of H3PO4, so, Mg(OH)2 is limiting reagent !
Now , we will use Mg(OH)2 in further calculation .
Molar mass of Mg3(PO4)2 = 262.87 g/mol
According to balanced equation :
mol of Mg3(PO4)2 formed = (1/3)* moles of Mg(OH)2
= (1/3)*0.5246
= 0.1749 moles of Mg3(PO4)2
use :
mass of Mg3(PO4)2 = number of mol * molar mass
= 0.1749 * 262.87
= 46 g of Mg3(PO4)2
Therefore:
% yield = actual mass * 100 / theoretical mass
% = 34.7 * 100 / 46
% = 3470 / 46
= 75.5%
Hope that helps!
Answer:
The mass of NaCl is 0.029 grams
Explanation:
Step 1: Data given
Molecular weight of NaCl = 58.44 g/mol
Volume of solution = 100 mL = 0.100 L
Molarity = 0.0050 M
Step 2: Calculate moles NaCl
Moles NaCl = molarity * volume
Moles NaCl = 0.0050 M * 0.100 L
Moles NaCl = 0.00050 moles
Step 3: Calculate mass NaCl
Mass NaCl = moles NaCl * molar mass NaCl
Mass NaCl = 0.00050 moles * 58.44 g/mol
Mass NaCl = 0.029 grams
The mass of NaCl is 0.029 grams
