Eroded sediments from further upstream clogged Jakarta’s rivers and canals, causing them to overflow. Similar erosion-related floods have occurred in many other countries, such as Colombia, India, the Philippines and Democratic Republic of the Congo.
The standard heat of formation is the energy change that occurs when 1 mole of a substance is made from its elements in their standard states ( most stable form of the element at 1 bar of pressure and the specified temperature, usually 298 K or 25 degrees Celcius)
E.g for MgCO3
Mg (s) + C (s) + 3/2 O2 (g) = MgCO3
Answer: Molarity of the prepared solution is 
Explanation:
Molarity is defined as the number of moles of solute dissolved per liter of the solution.

where,
n= moles of solute
= volume of solution in ml = 500 ml
moles of solute =
Now put all the given values in the formula of molarity, we get

Thus molarity of the prepared solution is 
Answer: pH = 7.36. The pKa of H2PO4− is 7.21.
Explanation: