Answer:
Explanation:
We want to convert atoms of arsenic to mass in grams. We have to complete 3 steps.
<h3>1. Convert Atoms to Moles</h3>
The first step is converting atoms to moles. We use Avogadro's Number for this. This number is 6.022*10²³ and it is the number of representative units (molecules, atoms, etc.) in 1 mole of a substance. In this problem, the particles are atoms of arsenic. So, 1 mole of arsenic contains 6.022*10²³ atoms of arsenic. Use this information to make a ratio.
Multiply by the number of atoms provided in the problem: 4.83 × 10²¹
The units of atoms of arsenic (atoms As) cancel.
Condense into 1 fraction.
<h3>2. Convert Moles to Grams</h3>
The next step is converting moles to grams. We use the molar mass for this, which is provided. There are 74.92 grams of arsenic in 1 mole of arsenic, so we can make another ratio.
Multiply by the number of moles we calculated.
The units of moles of arsenic (mol As) cancel.
<h3>3. Round</h3>
The original measurement of atoms (4.83 × 10²¹ ) has 3 significant figures, so our answer must have the same.
For the number we calculated, that is the thousandth place. The 9 in the ten-thousandth place (0.6009026901) tells us to round the 0 to a 1.
There are approximately <u>0.601 grams of arsenic.</u>