Limestone is primarily a crystal form of caco 3 . how many moles of oxygen are in a 1.25 mol sample of caco 3 ? only include the numerical value in your answer. do not include units.

As the molecular formula of CaCO₃ suggested, that there are 3 moles of oxygen are there in 1 mole of CaCO₃.

So in 1.25 mol of CaCO₃ contains=1.25 ×3 moles of oxygen  

                                                    =3.75  moles of oxygen

So there are 3.75  moles of oxygen are there in 1.25 mol of CaCO₃.

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.