Answer:
Models help scientists understand processes in the natural world by providing simpler representations of those processes.
The correct answer:C) NaCl(s)
Hope this helps!
<span>Methink this is a neutralization reaction where an acid reacts with a base to form salt and water; but if we must balance the equation, we need to know what the product would be?
So our base LiOH reacts with our acid Tetraoxosulphate (VI) H2SO4. The reaction produces salt and water as evidence. LiOH + H2SO4 gives Li2SO4 and H20. We need to make sure that the total atoms on the LHS and RHS balanced. So adding two moles of LiOH, we have 2LiOH + H2SO4 produces LiSO4 + H20. The eqn isn't balanced yet as there's 2 moles of deficit H2 atoms on the RHS,
So our final reaction we have 2LiOH + H2SO4 gives Li2SO4 + 2H2O. Hence our answer is C</span>
To answer this question, you need to know the concept of half-life, which is how a radioactive material decreases in mass over time.
The half life of U-235 is 703.8 million years. The first part of this problem is to find the scale factor. To do this, divide the time that has past by the half life, like this:

Now, take this scale factor and multiply it by the current mass, like this:

This number is what you add to the current mass to get the original mass. That is because the scale factor showed us that it was just over one half life. Since after one half life, the mass is cut in half, and this is over one half life, when we add to the original it will be a little over double. This equation illustrates the final addition:

I hope this helped you. Fell free to ask any further questions.