Question

1-Convert the following to moles: 6.8 x 10^23 molecules of water

Answer 1

Answer:

1.1 mol H₂O

General Formulas and Concepts:

Chemistry

• Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
• Dimensional Analysis

Explanation:

Step 1: Define

6.8 × 10²³ molecules H₂O

Step 2: Convert

$6.8 \cdot 10^{23} \ mc \ H_2O(\frac{1 \ mol \ H_2O}{6.022 \cdot 10^{23} \ mc \ H_2O} )$ = 1.12919 mol H₂O

Step 3: Check

We are given 2 sig figs. Follow sig fig rules.

1.12919 mol H₂O ≈ 1.1 mol H₂O

Answer 2

Answer:

Our final conversion is 1.1 moles of water.

Explanation:

When we want to find the amount of moles in a substance, we can use dimensional analysis or conversion factors in order to convert it from molecules, grams, atoms, formula units, or virtually any other unit.

We are given that we want to convert 6.8 x 10²³ molecules of water to moles. We can set up a dimensional analysis table to solve this.

In dimensional analysis, we multiply across the top and then divide the results by the multiplied value on the bottom.

$\begin{tabular}{c|c}6.8 \times 10^{23} \ \text{molec. of water} & \text{1 mol H}_2 \text{O} \\ \cline{1-2} 1 & 6.022 \times 10^{23} \ \text{molec. of water} & \end{tabular}$

Now, we will perform our calculations and find our final answer.

$(6.8 \times 10^{23}) \times (1) = 6.8 \times 10^{23}$

$(1) \times (6.022 \times 10^{23}) = 6.022 \times 10^{23}$

$\huge\frac{6.8 \times 10^{23}}{6.022 \times 10^{23}} = 1.129192959$

$\text{Round to significant figures} \rightarrow 1.129192959 \approx 1.1$

Therefore, using our table, we have determined that our final answer is 1.1 moles of water.

$\begin{tabular}{c|c}6.8 \times 10^{23} \ \text{molec. of water} & \text{1 mol H}_2 \text{O} \\ \cline{1-2} 1 & 6.022 \times 10^{23} \ \text{molec. of water} & \end{tabular} = 1.1 \text{moles of water}$