Answer: 63.26%
Explanation:
If we let the abundance of the first isotope be x, then:

Which is equal to <u>63.26%</u>
The molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.
<u>Explanation:</u>
Molality is the measure of how much of amount of solute is dissolved in the solvent. So it is calculated as the ratio of moles of solute to the grams of solvent.

As in this case, the solute is NaCl and solvent is unknown. So the moles of solute is given as 1.34 moles and the mass of solvent is given as 2.47 kg.
Hence, 
Thus, the molality is 0.54 M when 1.34 moles of NaCl is present in 2.47 kg of solvent.
Answer:
A) Age!! Its because even if the object was 1 year old or 100 years old, nothing about the impact would change. However, those other categories depict features that would definitely make an impact. For example as object that is big, fast, and hits at an angle perpendicular to whatever it is moving towards, the impact will be very lage. But if its the opposite and it was small and slow, then the impact crater would not be as large. Good luck on your quiz!!
Answer: Silicon the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Silicon go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons.
Hope this helps! :)