Answer:
x = 33.52 amu
Explanation:
It is given that,
Isotope A has a mass of 34 amu and an abundance of 52%, isotope B has a mass of 33 amu and an abundance of 48%.
Let x is the average atomic mass of this element. It can be calculated as follows :

So, the average atomic mass of this element is 33.52 amu.
B) energy is absorbed by the reaction
is right answer.
Answer: 
Explanation:
25.3% Mg
74.7% Cl
First step: change % to g
25.3g Mg
74.7g Cl
Second step: calculate g/mol of each compound. You can do this by using the atomic mass.


Third step: determine the lowest number and divide everything by it. Of the result, extract whole number only.


Fourth step: Write each compound with their respective number below.
This empirical formula should be: 
Answer:
B. oxygen and glucose
Explanation:
Oxygen for respiration and glucose for energy utilization
<span>The solution to the problem is as follows:
125/58.69 = 2.12 mol
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Therefore, there are 2.12 moles of <span>nickel (Ni) atoms are in 125 g Ni.
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