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Rus_ich [418]
3 years ago
8

How much heat in kj is released by burning 9.5 grams of methane?

Chemistry
1 answer:
tatyana61 [14]3 years ago
7 0
Methane is the compound CH4, and burning it uses the reaction:

CH4 + O2 -> CO2 + H2O, which is rather exothermic. To find the heat released by burning a certain amount of the substance, you should look at the bond enthalpy of each compound, and then compare the values before and after the reaction. In methane, there are 4 C-H bonds, which have bond energy of 416 kj/mol, resulting in a total bond energy of 1664 kj/mol. O2 is 494 kj/mol. Therefore we have a total of 2080 kj/mol on the left side. On the right side we have CO2, which has 2 C=O bonds, each at 799 kj/mol each, resulting in 1598 kj/mol, and H2O has 2 O-H bonds, at 459kj/mol each, resulting in a total of 2516 kj/mol on the right hand side. Now, this may be confusing because the left hand side seems to have less heat than the right, but you just need to remember: making minus breaking, which results in a total change of 436kj/mol heat evolved.

Now it is a simple matter of find the mols of CH4 reacted, using n=m/mr.

n = 9.5/16.042 = 0.592195 mol

Therefore, if we reacted 0.592195 mol, and we produced 436 kj for one mol, the total amount of energy evolved was 436*<span>0.592195 kj, or 258.197 kj.</span>
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A pharmacist has calculated that a patient requires 30 mmol of phosphate and 80 meq of potassium to be added to the pn. how many
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Since potassium and phosphate is what we are to find for and they are both found in the potassium phosphate solution, therefore we solve for this one first on the basis of the phosphate.

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If a reaction occurs when a piece of metal is placed in a solution, what can you conclude about the solution?
USPshnik [31]
Hello!

If a reaction occurs when a piece of metal is placed in a solution, you can conclude that the solution is <span>probably acidic because bases rarely react with metals.

Strong Acids, like HCl, react with metals to produce salts and release gaseous hydrogen (H</span>₂) which is evidenced by the generation of bubbles in the solution. The general chemical equation for this kind of reactions for a metal M and an acid HA is:

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Have a nice day!
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</span>
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3 years ago
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