Plz help me with these three please please !!!!!
1 answer:
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Answer:
4.51 × 10³ kcal
B. less
Explanation:
Let's consider the combustion of 2-methylheptane.
C₈H₁₈ + 12.5 O₂ ⇒ 8 CO₂ + 9 H₂O
When 1 mole of C₈H₁₈ burns, 1.306 × 10³ Kcal are released (heat of combustion). The molar mass of C₈H₁₈ is 114 g/mol. Then, for 394 g of C₈H₁₈:
<em>Assuming the same efficiency, would 394 grams of ethanol provide more, less, or the same amount of energy as 394 grams of 2-methylheptane?</em>
Let's consider the combustion of ethanol.
C₂H₆O + 3 O₂ ⇒ 2 CO₂ + 3 H₂O
When 1 mole of C₂H₆O burns, 326.7 Kcal are released (heat of combustion). The molar mass of C₂H₆O is 46.0 g/mol. Then, for 394 g of C₂H₆O:
The combustion of 394 g of ethanol provides less energy than the combustion of 394 g of 2-methylheptane.
Answer:- mass of water is 0.15 g.
Solution:- This problem is based on the formula:
where, q is the heat energy, m is mass, is specific heat and
is change in temperature.
= final temperature - initial temperature
= 37.0 - 5.0 = 32.0 degree C
m = ?
q = 20.0 J
Let's plug in the values in the formula:
m = 0.15 g
So, the mass of water for the given problem is 0.15 g.