1. How many moles of atoms are contained in 21.0 g of Br 2 ? 2. 1.28 x 10 24 ato

Question

1. How many moles of atoms are contained in 21.0 g of Br2 ?

2. 1.28 x 1024atoms of S. (Calculate the number of grams)

3. How many atoms are contained in (5 molecules CH3COOH) and (12.0 mol H2O)

4. calculate the number of grams of hydrogen in 8.44 mol H2SO4

5. A. What is the element of ( 65.2 g sample of a compound containing 36.8 g silver, 12.1 g chlorine, and the rest, oxygen)

B. compound containing 38.0 g zinc and 12.0 g phosphorous)

6. How many grams of oxygen are contained in 8.50 g of Al2(SO4)3?

7. Copper is often added to paint for ocean-going ships and boats to discourage the growth of marine organisms on their hulls. Unfortunately, the copper dissolves into the water and is toxic to the marine life in harbors where these boats are docked. When copper(II) ions reach a concentration of 9.0 micrograms/liter, the growth of some marine life slows. How many copper ions are found in a liter of water containing 5.8 micrograms of Cu2+ per liter?

___x10^-- Cu2+ ions

Please anyone, I need help if you can do any of these?

Explanation / Answer

1)

Molar mass of Br2 = 159.8 g/mol

mass(Br2)= 21.0 g

number of mol of Br2,

n = mass of Br2/molar mass of Br2

=(21.0 g)/(159.8 g/mol)

= 0.131 mol

Answer: 0.131 mol

2)

molar mass of S = 32.07 g/mol

This is mass of 6.022*10^23 atoms

so, mass of 1 atom = molar mass /(6.022*10^23)

mass of 1 atom = 32.07/(6.022*10^23)

mass of 1 atom = 5.316*10^-23 g

mass of 1.28*10^24 atom = mass of 1 atom * total number of atoms

= 1.28*10^24 * 1.28*10^24

= 68.0 g

Answer: 68.0 g

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