How many elements make up each of the following molecules? H2O, O2, C6H12O6, NaHCO3. How many atoms make up each of the following molecules? H2O, O2, C6H12O6, NaHCO3. Calculate the... How many elements make up each of the following molecules? H2O, O2, C6H12O6, NaHCO3. How many atoms make up each of the following molecules? H2O, O2, C6H12O6, NaHCO3. Calculate the molar mass of each of the following molecules: H2O, CO2. Convert mass (grams) to moles (mol) for KCl and sodium carbonate. Convert mass (grams) to moles (grams) for Br2 and iodine gas. Convert mass (grams) to molecules for NO2 and lithium nitride. Read more

Steps to Solve

1. Identify Elements in Molecules

   To find the number of elements in each molecule, count the unique types of atoms present:

   • For $H_2O$: 2 elements (Hydrogen and Oxygen)
   • For $O_2$: 1 element (Oxygen)
   • For $C_6H_{12}O_6$: 3 elements (Carbon, Hydrogen, Oxygen)
   • For $NaHCO_3$: 4 elements (Sodium, Hydrogen, Carbon, Oxygen)

2. Identify Atoms in Molecules

   Count the total number of atoms in each molecule:

   • For $H_2O$: 3 atoms (2 H + 1 O)
   • For $O_2$: 2 atoms (2 O)
   • For $C_6H_{12}O_6$: 24 atoms (6 C + 12 H + 6 O)
   • For $NaHCO_3$: 6 atoms (1 Na + 1 H + 1 C + 3 O)

3. Calculate Molar Mass

   Use the atomic masses from the periodic table to calculate the molar mass for each molecule:

   • For $H_2O$: [ \text{Molar mass} = (2 \times 1.008) + (1 \times 16.00) = 18.016 , \text{g/mol} ]
   • For $CO_2$: [ \text{Molar mass} = (1 \times 12.01) + (2 \times 16.00) = 44.01 , \text{g/mol} ]

4. Convert Mass to Moles

   For the following examples, use the formula: [ \text{Moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} ]

   • For 84.03 g KCl: [ \text{Moles} = \frac{84.03}{74.55} \approx 1.127 , \text{mol} ]
   • For 55.42 g sodium carbonate ($Na_2CO_3$): [ \text{Molar mass of } Na_2CO_3 = (2 \times 22.99) + (1 \times 12.01) + (3 \times 16.00) = 105.99 , \text{g/mol} ] [ \text{Moles} = \frac{55.42}{105.99} \approx 0.523 , \text{mol} ]

5. Convert Moles to Grams

   Use the formula: [ \text{Mass (g)} = \text{moles} \times \text{molar mass (g/mol)} ]

   • For 2.56 mol Br: [ \text{Mass} = 2.56 \times 159.8 \approx 409.0 , \text{g} ]
   • For 0.567 mol iodine gas ($I_2$): [ \text{Molar mass of } I_2 = 2 \times 126.90 = 253.80 , \text{g/mol} ] [ \text{Mass} = 0.567 \times 253.80 \approx 147.0 , \text{g} ]

6. Convert Mass to Molecules

   To find number of molecules: [ \text{Number of molecules} = \text{moles} \times 6.022 \times 10^{23} ]

   • For 9.31 g $NO_2$: [ \text{Moles} = \frac{9.31}{46.01} \approx 0.202 , \text{mol} ] [ \text{Molecules} = 0.202 \times 6.022 \times 10^{23} \approx 1.22 \times 10^{23} , \text{molecules} ]
   • For 32.81 g lithium nitride ($Li_3N$): [ \text{Molar mass of } Li_3N = (3 \times 6.94) + (1 \times 14.01) = 34.83 , \text{g/mol} ] [ \text{Moles} = \frac{32.81}{34.83} \approx 0.942 , \text{mol} ] [ \text{Molecules} = 0.942 \times 6.022 \times 10^{23} \approx 5.67 \times 10^{23} , \text{atoms} ]