Question

1. When 90 grams of water is evaporated, how many atoms of hydrogen was lost?

2. How many picoliters of water are in 3.32 mol of water?

3. How many centiliters of sulfuric acid are in 32.9 x 10^-23 molecules of acid? The density of sulfuric acid is 1.84 g/cm³.

4. How many daL of bromine are in 15.7 x 10²² molecules? (The density of bromine is 3.1 g/cm³)

5. How many daL of bromine atoms are in 9- x 10²² bromine atoms? (The density of bromine is 3.1 g/cm³)

6. How many ng of lithium are in 83.3 pg of lithium nitrate pentahydrate?

7. How many fg of hydrogen are in 8.0 mg of strontium hydride?

8. How many hg of oxygen are in 9.999 pg of cobaltous phosphite nanohydrate?

Answer 1

1)

Molar mass of H2O = 2*MM(H) + 1*MM(O)

= 2*1.008 + 1*16.0

= 18.016 g/mol

mass of H2O = 90 g

we have below equation to be used:

number of mol of H2O,

n = mass of H2O/molar mass of H2O

=(90.0 g)/(18.016 g/mol)

= 4.996 mol

we have below equation to be used:

number of molecules = number of mol * Avogadro’s number

number of molecules = 4.996 * 6.022*10^23 molecules

number of molecules = 3.008*10^24 molecules

Total number of H atoms in 1 molecule = 2

we have below equation to be used:

number of atoms = number of molecules * Total number of atoms in 1 molecule

number of atoms = 3.008*10^24 * 2

number of atoms = 6.02*10^24

Answer: 6.02*10^24 atoms

Only 1 question at a time please