 How many moles are in the following:
a. 1.29 x 1024 hydrogen atoms in HF
b. 7.36 x 1024 free oxygen atoms
c. 3.28 x 1023 Na atoms in salt (NaCl)
 How many atoms are present in the following?
a. Hydrogen atoms in 3.14 mol of H2O
b. Nitrogen atoms in 2.79 mol of NH3
c. Oxygen atoms in 4.90 mol in Al2O3
 How many atoms are in a 3.56 g sample of Cu? Is this a mol of Cu?
 What mass of Ni has as many atoms as there are N atoms in 63.0 g of NO 2? As Na atoms in 63.0 g of
NaCl?
 How many g of CaCO3 are present in a sample if there are 4.52 x 10 24 atoms of carbon in that sample?
 How many molecules of HCl are in 4.91 L of HCl acid at 25�C if the density equals 1.096 g/mL?
 If a 1.000 gallon (3.785 L) bottle were filled with bleach (NaClO), how many Cl atoms would be in the
bottle? bleach = 1.090 g/mL
 At 25º C, the density of water is 0.997 g/ml. At -10º C, the density of ice is 0.917 g/cm3. If a bottle with a
volume of 275 mL were filled fully with water at 25º C and then frozen to -10º C, could the ice still be
contained in the bottle? What would the volume of the ice be?
 How many moles are in the following:
a. 1.29 x 1024 hydrogen atoms in HF
b. 7.36 x 1024 free oxygen atoms
2.14 moles H atoms
12.2 moles O atoms
c. 3.28 x 1023 Na atoms in salt (NaCl)
0.545 moles Na atoms
 How many atoms are present in the following?
a. Hydrogen atoms in 3.14 mol of H2O
3.78 x 1024 H atoms
b. Nitrogen atoms in 2.79 mol of NH3
1.68 x 1024 N atoms
c. Oxygen atoms in 4.90 mol in Al2O3
8.85 x 1024 O atoms
 How many atoms are in a 3.56 g sample of Cu? Is this a mol of Cu? 3.37 x 1022 Cu atoms
 What mass of Ni has as many atoms as there are N atoms in 63.0 g of NO 2? As Na atoms in 63.0 g of
NaCl? 80.4 g Ni, 63.3 g Ni
 How many g of CaCO3 are present in a sample if there are 4.52 x 10 24 atoms of carbon in that
sample? 751 g CaCO3
 How many molecules of HCl are in 4.91 L of HCl acid at 25�C if the density equals 1.096 g/mL? 8.89
x 1025 molecules
 If a 1.000 gallon (3.785 L) bottle were filled with bleach (NaClO), how many Cl atoms would be in the
bottle? bleach = 1.090 g/mL
3.34 x 1025 Cl atoms
 At 25º C, the density of water is 0.997 g/ml. At -10º C, the density of ice is 0.917 g/cm3. If a bottle with a
volume of 275 mL were filled fully with water at 25º C and then frozen to -10º C, could the ice still be
contained in the bottle? What would the volume of the ice be?
No. 253 mL