Question

What is the mass of 0.452 moles of methane, CH4?
What is the mass of 1.55 moles of N2O?
What is the mass of 3.28 moles of dinitrogen tetroxide?
What is the mass of 1.95 moles of potassium phosphate ?
What is the mass of 10.5 moles of hydrogen, H2?

Answer 1

Answer on Question #59406 - Chemistry - General Chemistry

Task (1): What is the mass of 0.452 moles of methane, CH₄?

Solution (1):

The formula mass methane is the sum of the atomic masses for each atom in the compound. Then,

$$1(C) + 4(H) = 1 \times 12 + 4 \times 1 = 16 \frac{g}{mole} CH_4.$$

One mole of methane (CH₄) has a mass of 16.0 g.

Let us find the mass that is 0.452 moles of methane:

$$0.452 \, \text{mole} \times \left[ \frac{16.0 \, \text{g} \, \text{CH}_4}{1 \, \text{mole} \, \text{CH}_4} \right] = 7.232 \, \text{g} \, \text{CH}_4.$$ $$m(CH_4) = 7.232 \, \text{g}$$

Answer (1): $m(CH_4) = 7.232 \, \text{g}$ are in 0.452 moles of methane (CH₄).

Task (2): What is the mass of 1.55 moles of N₂O?

Solution (2):

The formula mass N₂O is the sum of the atomic masses for each atom in the compound. Then,

$$2(N) + (O) = 2 \times 14 + 1 \times 16 = 44 \frac{g}{mole} N_2O.$$

One mole of N₂O has a mass of 44.0 g.

Let us find the mass that is 1.55 moles of N₂O:

$$\begin{array}{l} 1.55 \text{ mole} \times \left[ \frac{44.0 \text{ g } N_2O}{1 \text{ mole } N_2O} \right] = 68.2 \text{ g } N_2O. \\ m(N_2O) = 68.2 \text{ g} \end{array}$$

Answer (2): $m(N_2O) = 68.2g$ are in 1.55 moles of $N_2O$.

Task (3): What is the mass of 3.28 moles of dinitrogen tetroxide?

Solution (3):

The formula mass dinitrogen tetroxide $(N_2O_4)$ is the sum of the atomic masses for each atom in the compound.

Then,

$$2(N) + 4(O) = 2 \times 14 + 4 \times 16 = 92 \frac{g}{\text{mole } N_2O_4}.$$

One mole of N2O4 has a mass of $92.0\,\text{g}$.

Let us find the mass that is 3.28 moles of $N_2O_4$:

$$3.28 \text{ mole} \times \left[ \frac{92.0 \text{ g } N_2O_4}{1 \text{ mole } N_2O_4} \right] = 301.76 \text{ g } N_2O_4.$$ $$m(N_2O_4) = 301.76 \text{ g}$$

Answer (3): $m(N_2O_4) = 301.76g$ are in 3.28 moles of dinitrogen tetroxide $(N_2O_4)$.

Task (4): What is the mass of 1.95 moles of potassium phosphate?

Solution (4):

The formula mass potassium phosphate $(\mathrm{K}_3\mathrm{PO}_4)$ is the sum of the atomic masses for each atom in the compound.

Then,

$$3 (K) + 1 (P) + 4 (O) = 3 \times 39 + 1 \times 31 + 4 \times 16 = 212 \frac{g}{mole} K_3PO_4.$$

One mole of $\mathrm{K}_3\mathrm{PO}_4$ has a mass of $212.0~\mathrm{g}$

Let us find the mass that is 1.95 moles of K3PO4:

$$1.95 \, \mathrm{mole} \times \left[ \frac{212.0 \, \mathrm{g} \, K_3PO_4}{1 \, \mathrm{mole} \, K_3PO_4} \right] = 413.4 \, \mathrm{g} \, K_3PO_4.$$ $$m (K_3PO_4) = 413.4 \, \mathrm{g}$$

Answer (4): $\mathrm{m}(\mathrm{K}_3\mathrm{PO}_4) = 413.4\mathrm{g}$ are in 1.95 moles of potassium phosphate $(\mathrm{K}_3\mathrm{PO}_4)$

Task (5): What is the mass of 10.5 moles of hydrogen, $\mathrm{H}_2$?

Solution (5):

The formula mass hydrogen $(\mathrm{H}_2)$ is the sum of the atomic masses for each atom in the compound.

Then,

$$2 (H) = 2 \times 1 = 2 \frac{g}{mole} H_2.$$

One mole of $\mathrm{H}_2$ has a mass of $2~\mathrm{g}$

Let us find the mass that is 10.5 moles of $\mathrm{H}_2$:

$$10.5 \text{mole} \times \left[ \frac{2.0 \text{g } H_2}{1 \text{mole } H_2} \right] = 21.0 \text{g } H_2.$$ $$m(H_2) = 21.0 \text{g}$$

Answer (4): $m(H_2) = 21.0 \text{g}$ are in 1.05 moles of hydrogen (H2).

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