# Chemistry

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When 0.250 mol of CH4(g) reacts with excess Cl2(g) at constant pressure according to the chemical equation shown below, 177 kJ of heat are released. Calculate the value of Delta H for this reaction, as written.

2CH4(g)+3Cl2(g)-->2CHCl3(l)+3H2(g)

delta H=?

• Chemistry -

If 1/4 mole releases 177 kJ, then 1 mole will release 4x that and 2 moles will release 8x that. Check my thinking.

• Chemistry -

+1420kJ?

• Chemistry -

I get 1416 kJ. If you rounded your answer because of significant figures, showing it as 1420 won't do it. Most texts recommend writing it as 1.42 x 10^3 kJ.

• Chemistry -

hhmm would it be 4x that amount and not 8? im confused

• Chemistry -

moles = grams/molar mass
0.25 = g/16 and grams = 0.25 x 16 = 4 grams.
The equation as written is 2 moles CH4 so that is 16 x 2 = 32 grams.
177 kJ (for the reaction for the 4 grams) x (32/4) = ??

• Chemistry -

i guess the teacher put a bad answer bank none of the answer are 1416 but i get what you are saying i will bring this up to him thanx

• Chemistry -

Try 1.42 x 10^3 kJ and let me know.