[ike1047]

i cant figure this out?

(a) write balanced equation for the reaction of potassium metal with water?

(b) calculate change in heat for the reaction of potassium metal in water

(c) Assume that a chunk of potassium weighting 7.55 g is dropped into a 400.00 g of water at 25.0 degrees celcuis. What is the final temperature of the water if all the heat is released is used to warm the water?

(d) what is the molarity of KOH solution in part (c) and how many milliliters of 0.554M H2SO4 are required to neutalize it? Assume a solution density of 1.00 g/mL

if you get a right you get a prize ;]

[EDIT: Title made more appropriate - Dan]

[english]

(a) Potassium metal is K_(s).  This one is straight forward.

(b) In other words, what is the heat of reaction (H_rxn) for this reaction?  What are the H °_f values for potassium metal and water?

(c) q = -q

where q = mc(T_final - T_initial)

m = mass
c = 4.184 J/g*K
T = temperature

(d) Look up the definition of molarity.  What are its units?  Using this information, you can say that x mol of KOH is neutralized by x mol of H₂SO₄ per unit of volume.

Use the chemical equilibrium of KOH and H₂SO₄ to get the molar ration of KOH:H₂SO₄.  This will allow you to calculate how many moles of H₂SO₄ you will need.  If you already know that there are .554 mol of H₂SO₄ per Liter of solution, then how many Liters of solution is x moles you just found?


Hint:  To get the volume of KOH/H₂O solution, use the density of water (1.998 g/L) to calculate how many Liters of water is 400.00g.

[Borek]

Please read forum rules. Your luck k.V. forgot about them.

[english]

Please read forum rules. Your luck k.V. forgot about them.