Use Avogadro\'s number to do the following Show work, use How many atoms are the

Question

Use Avogadro's number to do the following Show work, use How many atoms are there in 0.00150 moles Zn b. If you had 2.50 moles of oxygen gas, what mass of the gas would be in the sample? what mass cH c A 407 g sample of NaT contains how many atoms of Na? 9. The of th d. How many atoms of chlorine are there in 16.5 g of iron (III) chloride, FeCl3? e What is the mass of 100 million atoms of gold? Could you mass this on a 6. Calculate the empirical formula of a compound that contains 4.20 g of nitrogen and 12.0g of oxygen 7. When 20.16 g of magnesium oxide reacts with carbon, carbon monoxide forms and 12.16 g of Mg metal remains. What is the empirical formula of magnesium oxide? Unit 4-Counting Particles Toe Small To See 26 of 27

Explanation / Answer

5.

(a)

1 mol of Zn = 6.022 * 1023 atoms            ( Avagadro's number)

then, 0.00150 mol of Zn = 0.00150 * 6.022 * 1023 = 0.009033 * 1023 = 9.033 * 1020 atoms of Zn

(b)

Number of Moles = mass / molar mass

Mass of oxygen = 2.50 * 32.0 = 80.0 g.

(c)

Molar mass of NaI = 150. g/mol

Number of moles of NaI = mass / molar mass = 4.07 / 150. = 0.0271 mol

1 mol of NaI has 1 mol of Na atoms

then,

0.0271 mol of NaI has 0.0271 mol of Na atoms.

Number of Na atoms = 0.0271 * 6.022 * 1023 = 1.63 * 1022 atoms

(d)

Molar mass of FeCl3 = 162.5 g/mol

Number of moles of FeCl3 = mass / molar mass = 16.5 / 162.5 =0.102 mol

1 mol of FeCl3 has 3 mol of Cl

then,

0.102 mol of FeCl3 has 3 * 0.102 = 0.306 mol of Cl atoms

Number of Cl atoms = 0.306 * 6.022 * 1023 = 1.83 * 1023 atoms

(e)

Number of atoms of Au = 100 million = 100 * 106 atoms = 108 atoms

6.022 * 1023 atoms of Au = 197 g.

108 atoms of Au = 108 * 197 / (6.022 * 1023) = 3.27 * 10-14 g.

It is not possible to weigh on a balance.

Related Questions

Navigate

• Browse (All)
• Browse U
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.