694,563,239 rounded to the nearest thousand is 694,563.
It's because the first digit from the right is for ones, second for tens, third for hundreds and fourth for thousands and that's the one that we should take a closer look at. You can round it either to 3 or 4, depends on the digit of hundreds. In this case 3239 is clearly closer to 3000 than 4000, that's why we round it to 694,563, not 694,564.
The amount of sample that is left after a certain period of time, given the half-life, h, can be calculated through the equation.
A(t) = A(o) (1/2)^(t/d)
where t is the certain period of time. Substituting the known values,
A(t) = (20 mg)(1/2)^(85.80/14.30)
Solving,
A(t) = 0.3125 mg
Hence, the answer is 0.3125 mg.
PLEASE HELP I HAVE TO DO THIS BENCHAMRK QUESTION!!!
The chart shows parts of a plant and an animal, at different levels of organization. Consider the plant images. If we are referring to levels of organization in a plant which picture can BEST be used to fill in box Y?
first picture (A
<u>Answer:</u> The atomic symbol of the given element is 
<u>Explanation:</u>
The general isotopic representation of an element is given as: 
where,
Z represents the atomic number of the element
A represents the mass number of the element
X represents the symbol of an element
For the given isotope: 130-iodine
Mass number = 130
Atomic number = 53
Hence, the atomic symbol of the given element is
