Answer:

Explanation:
Hello,
In this case, we can consider that the given heat of combustion is indeed the heat of reaction since it corresponds to the combustion of propane, which is computed by using the heat formation of all the involved species as shown below:

Thus, since the heat of formation of gaseous carbon dioxide is -393.5 kJ/mol, water -241.8 kJ/mol and oxygen 0 kJ/mol, the heat of formation of propane is:

Best regards.
Answer:
87.27 grams
Explanation:
The mole ratio of nitrogen to hydrogen is 1:3; while that one of hydrogen to the products (ammonia) is 3:2
Thus if 3 moles of hydrogen gas produce 2 moles of ammonia gas
7.7 moles of hydrogen will produce:
(7.7moles×2)/3
77/15 moles
1 mole of ammonia gas has a mass of 14+3=17
since the mass of an atom of nitrogen is 14 while that of hydrogen atom is 1.
Therefore 77/15 moles will have a mass of
77/15 moles × 17=87.27 grams
I don't know about 14, but 15 is (4), because a liquid draws in heat to turn into a gas. 16 is (2), because to turn into a cold solid, something has to release heat.
1 mm (millimeter) = 0.000001 km (kilometer)
12.5 mm = <span>0.0000125 km
1 mm = </span><span>0.00001 hm (hectometer)
12.5 mm = </span><span>0.000125 hm
1 mm = </span>0.001 m (meter)
12.5 mm = 0.0125 m
1 mm = 0.1 cm (centimeter)
12.5 mm = 1.25 cm
So the only one of the answer choices that doesn't equal 12.5 mm is 0.00125 hm, since 12.5 mm is <span>0.000125 hm.
Answer:
</span><span>0.00125 hm
</span><span>
Hope this helps!</span>