Answer:
Q = -33.6kcal .
Explanation:
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In this case, according to the equation for the calculation of the total heat of reaction when a fixed mass of a fuel like ethane is burnt, we can write:

Whereas n stands for the moles and the other term for the enthalpy of combustion. Thus, for the required total heat of reaction, we first compute the moles of ethane in 3 g as shown below:

Next, we understand that -337.0kcal is the heat released by the combustion of 1 mole of ethane, therefore, to compute Q, we proceed as follows:

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Answer:
Ca^+2
Explanation:
Hence, the correct option is A.
Answer:a formula giving the number of atoms of each of the elements present in one molecule of a specific compound.
Explanation:
The cell membrane acts as a semi-permeable barrier in plants. In other words, is in charge or control of what comes in and out of the cell.
Answer:
I think the answer is the 3rd one