<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> ####