Number of moles

Expresses the relative number (amount) of moles

Select the correct equation for calculating number of moles (n).

State all the mole formulas

How many moles are in 16.94g of water?

<ol> <li>Mole Calculation Review:</li> </ol> <p>a. To calculate the number of moles from grams, we use the formula:</p> <p>moles = mass (g) / molar mass (g/mol)</p> <p>The molar mass of NaCl (Sodium Chloride) is approximately 58.44 g/mol and the molar mass of Na2CO3 (Sodium Carbonate) is approximately 105.99 g/mol.</p> <p>i. For 55 g of NaCl:</p> <pre><code> moles = 55 g / 58.44 g/mol = 0.94 moles </code></pre> <p>ii. For 0.025 g of Na2CO3:</p> <pre><code> moles = 0.025 g / 105.99 g/mol = 0.00024 moles </code></pre> <p>b. To calculate the mass in grams from moles, we use the formula:</p> <p>mass (g) = moles * molar mass (g/mol)</p> <p>i. For 0.5 moles of NaCl:</p> <pre><code> mass = 0.5 moles * 58.44 g/mol = 29.22 g </code></pre> <p>ii. For 2.11 moles of Na2CO3:</p> <pre><code> mass = 2.11 moles * 105.99 g/mol = 223.64 g </code></pre> <ol start="2"> <li>Molarity (mol/L) is a measure of concentration. It represents the number of moles of a substance per liter of solution.</li> </ol> <p>a. mol/L means moles per liter. It is a unit of concentration that tells us how many moles of a substance are present in one liter of solution.</p> <p>b. mol/L and grams/liter are both measures of concentration. The main difference between them is what they are measuring. mol/L measures the number of moles of a substance per liter of solution, while grams/liter measures the mass of the substance per liter of solution. The similarity is that both are used to express the concentration of a solution. However, mol/L takes into account the molecular weight of the substance, while grams/liter does not.</p> ####