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The molecular formula of TCDD is C12H4O2Cl4. Chlorine exists as two isotopes 35Cl (75%) and 37Cl (25%). How many molecular ion peaks are there? What is the mass of the most abundant one?

Because chlorine exists as two isotopes, two molecular ions will be present, and their relative heights will correspond to the abundances of the isotopes. The tallest peak will be 3 times the height of the s...
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Answered by Ana D. Chemistry tutor
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What is the mass percentage of carbon in a CO2 molecule?

First we need to calculate the total mass of a CO 2 molecule. This is done by summing up the individual masses of all the atoms. To find these, we look at the periodic table and see that the masses are C: 12...
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Answered by Ana D. Chemistry tutor
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How can I stop my essays being too narrative?

This is a really common pitfall, because it is tempting just to tell the examiner everything you know and get carried away telling the story. I find the best way to avoid this is to really think about and an...
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Answered by Tilly G. History tutor
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explain why the electronegativity of fluorine is greater than that chlorine

The electrons in chlorine are further away from the nucleus and in a higher energy level (3p for chlorine as apposed to 2p for fluorine). Chlorines electrons are better shielded and so feel less nuclear char...
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Answered by Max G. Chemistry tutor
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What do you think might be the challenges of being a doctor?

This is a broad question which allows the candidate to show how they are aware of and possess the desirable qualities of a doctor. They can also be used to bring out effective coping strategies to ensure can...