How does matter and energy cycle through an ecosystem?
1 answer:
You might be interested in
Answer:
The result is 3.859 in which we use four significant figures.
Explanation:
We start by solving the mathematical operation :
The result for the operation is 3.859438 but the numbers in the operation are given with four significant figures and that is why we are going to use four significant figures to express the result
To express 3.859438 with four significant figures we use the first four digits that appear from left to right starting by the first digit that is different to zero
In this case : 3.859 will be the result with four significant figures.
We also use a rule that says : To decide if the last significant figure remains the same we look for the value of the digit at its right.
If that number is greater than or equal to 5 ⇒ we sum one to the last significant figure
For example 3.859738 = 3.860 with four significant figures because the ''7'' is greater that 5
If that number is less than 5 ⇒ the last significant figure remains the same
In our case : 3.859438 = 3.859 because ''4'' is less than ''5''
Answer:
11.45kcal/g
2.612 × 10³ kcal
Explanation:
When a compound burns (combustion) it produces carbon dioxide and water. The combustion of 2-methylheptane can be represented by the following balanced equation:
2 C₈H₁₈ + 25 O₂ ⇄ 16 CO₂ + 18 H₂O
It releases 1.306 × 10³ kcal every 1 mol of C₈H₁₈ that is burned.
<em>What is the heat of combustion for 2-methylheptane in kcal/gram?</em>
We know that the molar mass of C₈H₁₈ is 114.0g/mol. Then, using proportions:
<em>How much heat will be given off if molar quantities of 2-methylheptane react according to the following equation? 2 C₈H₁₈ + 25 O₂ ⇄ 16 CO₂ + 18 H₂O</em>
In this equation we have 2 moles of C₈H₁₈. So,