Answer:
20.67 kcal of energy is released.
Explanation:
It is given that, an exothermic reaction releases 86.5 kJ. We need to convet kJ to calories.
Since,
1 kcal = 4.184 kJ
So,
1 kJ = 0.239 kcal
For 86.5 kJ,
86.5 kJ = (0.239 × 86.5) kcal
86.5 kJ = 20.67 kcal
So, 20.67 kcal of energy is released.
Answer:
2Mg(s) +O₂(g) → 2MgO(s)
Explanation:
Mg(s) +O₂(g) → MgO(s)
When a chemical equation is balanced, the number of atoms of each element is equal on both sides of the arrow. We usually balance O and H last.
In this case, the number of Mg atoms is equal on both sides. Thus, let's move on to balance the O atoms. On the left side, there are 2 O atoms, while there is only 1 O atom on the left side. Thus, write a '2' in front of MgO.
Mg(s) +O₂(g) → 2MgO(s)
Now, the number of Mg atoms is not equal. Write a '2' in front of Mg to balance it.
2Mg(s) +O₂(g) → 2MgO(s)
The equation is now balanced with 2 Mg atoms and 2 O atoms on each side.
Proprietățile fizice ale mineralelor depind in cea mai mare măsură de compozitie chimică si structura reticulara reprezintă importanta deosebită în recunoașterea mineralelor
The molecular weight for Calcium Chloride Dihydrate (CaCl2•2H20) is 2H2O.
mass of 64g/mol = 256.52 g/mol
mass of 11g/mol = 26.981538 g/mol
mass of 147g/mol= 146.9149 g/mol
258g/mol = 258.09843 g/mol
