How many moles are in each of the following samples? (a) 11.51 g of Ti (b) 29.127 g of Na (c) 1.477 kg of U

Verified step by step guidance

1. <Determine the molar mass of each element from the periodic table: Ti (Titanium), Na (Sodium), and U (Uranium).>
2. <For each sample, use the formula: \( \text{moles} = \frac{\text{mass of sample (g)}}{\text{molar mass (g/mol)}} \) to calculate the number of moles.>
3. <For (a) 11.51 g of Ti, substitute the mass of Ti and its molar mass into the formula to find the moles of Ti.>
4. <For (b) 29.127 g of Na, substitute the mass of Na and its molar mass into the formula to find the moles of Na.>
5. <For (c) 1.477 kg of U, first convert the mass from kg to g, then substitute the mass of U and its molar mass into the formula to find the moles of U.>

Key Concepts

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a molecule or formula unit. For example, titanium (Ti) has a molar mass of approximately 47.87 g/mol, while sodium (Na) has a molar mass of about 22.99 g/mol. Knowing the molar mass is essential for converting between grams and moles.

Conversion from Grams to Moles

To convert grams of a substance to moles, you use the formula: moles = mass (g) / molar mass (g/mol). This relationship allows you to determine the number of moles present in a given mass of a substance. For instance, if you have 11.51 g of titanium, you would divide this mass by its molar mass to find the number of moles.

Unit Consistency

Unit consistency is crucial in chemistry calculations to ensure that all measurements are in compatible units. When converting mass to moles, it is important to use grams for mass and grams per mole for molar mass. Additionally, when dealing with larger quantities, such as kilograms, conversion to grams (1 kg = 1000 g) must be performed to maintain consistency in units throughout the calculation.