Part A What is the balanced chemical equation for the reaction used to calculate
ID: 712380 • Letter: P
Question
Part A
What is the balanced chemical equation for the reaction used to calculate Hf of MgCO3(s)?
If fractional coefficients are required, enter them as a fraction (i.e. 1/3). Indicate the physical states using the abbreviation (s), (l), or (g) for solid, liquid, or gas, respectively without indicating allotropes. Use (aq) for aqueous solution.
The standard enthalpy of formation (Hf) is the enthalpy change that occurs when exactly 1 mol of a compound is formed from its constituent elements under standard conditions. The standard conditions are 1 atm pressure, a temperature of 25 C , and all the species present at a concentration of 1 M . A "standard enthalpies of formation table" containing Hf values might look something like this: Substance Hf H(g) 218 kJ/mol H2(g) 0 kJ/mol Mg(s) 0 kJ/mol Mg2+(aq) 462.0 kJ/mol C(g) 71 kJ/mol C(s) 0 kJ/mol N(g) 473 kJ/mol O2(g) 0 kJ/mol O(g) 249 kJ/mol S2(g) 129 kJ/molExplanation / Answer
part A)
answer :
Mg(s) + C(s) + 3/2 O2 (g) ----------------> MgCO3 (s)
reason : this euqation is based on definition of standard enthalpy of formation . the definition is given above . that is " The standard enthalpy of formation (Hf) is the enthalpy change that occurs when exactly 1 mol of a compound is formed from its constituent elements under standard conditions"