Answer:
[tex]\boxed {\boxed {\sf 0.495 \ mol}}[/tex]
Explanation:
We are given a number of particles and asked to convert to moles.
1 mole of any substance contains the same number of particles (atoms, molecules, formula units) : 6.022 *10²³ or Avogadro's Number. For this question, the particles are not specified.
So, we know that 1 mole of this substance contains 6.022 *10²³ particles. Let's set up a ratio.
[tex]\frac { 1 \ mol }{6.022*10^{23 } \ particles}}[/tex]
We are converting 2.98*10²³ particles to moles, so we multiply the ratio by that value.
[tex]2.98*10^{23} \ particles *\frac { 1 \ mol }{6.022*10^{23 } \ particles}}[/tex]
The units of particles cancel.
[tex]2.98*10^{23} *\frac { 1 \ mol }{6.022*10^{23 } }}[/tex]
[tex]\frac { 2.98*10^{23}}{6.022*10^{23 } }} \ mol[/tex]
[tex]0.4948522086 \ mol[/tex]
The original measurement of particles (2.98*10²³) has 3 significant figures, so our answer must have the same.
For the number we found, 3 sig figs is the thousandth place.
The 8 in the ten-thousandth place (0.4948522086) tells us to round the 4 up to a 5 in the thousandth place.
[tex]0.495 \ mol[/tex]
2.98*10²³ particles are equal to approximately 0.495 moles.
