How many grams of oxygen are formed when 6.21 moles of koh are formed?
4 ko(s) + 2 h2o(l) → 4 koh(s) + o2(g)

From the given balanced chemical equation, it can be seen that for every 4 moles of KOH formed, only 1 mole of O2 is formed. From this ratio extracted from the equation, 
                   moles O2 = (6.21 moles) x (1 mole O2/4 moles KOH) 
                   moles O2 = 1.5525 moles O2
Then, we determine the mass in grams by multiplying the calculated value with the molar mass of oxygen, equal to 32. 
 The answer is therefore equal to 49.68 grams. 

You know how the first one if filled up like the objects do the same but with the other categories

Answer : option c) heat is released during the process.explanation :

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.