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Hydrates and Molar Volume of Gases. Section 11.5. What is a Hydrate?. A compound that has a specific number of water molecules bound to its atoms Examples: Sponges Opals CaCl 2 – Desiccant. Naming Hydrates. Desiccators.
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Hydrates and Molar Volume of Gases Section 11.5
What is a Hydrate? A compound that has a specific number of water molecules bound to its atoms Examples: Sponges Opals CaCl2 – Desiccant
Desiccators • * The anhydrous form of a hydrate used to absorb water. • *Anhydrous compounds can be packaged with materials that need to be kept moisture free • Can you think of any examples?
Steps to Determining Anhydrous Formulas • Determine the number of moles of the compound by dividing the mass by the molar mass. • Determine the number of moles of water by dividing the mass by the molar mass. • 3. Divide by the smallest number of moles. • Determine the ratio. • Please Copy the Steps Down!!!!
Hydrates Practice Problems What is the mole ratio of the hydrate CuSO4 . ____ H2O, if the anhydrous mass of the CuSO4 is 25.42g and the mass of the water is 14.3g? What is the mole ratio of the hydrate Na2CO3 . _____ H2O, if the original mass of the hydrated Na2CO3 was 43.69 g and the mass of the anhydrous Na2CO3 is 16.19 g? Determine the empirical formula for a compound found to contain 25.38 g of Mg and 74.62 g of Cl by mass. Determine the empirical formula for a compound that contains 32.88 % Carbon, 1.37 % Hydrogen, and 65.75 % Oxygen by mass.
Molar Volume of Gases Avogadro’s Principle states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles. The Molar Volume for a gas is the volume that one mole occupies at 0°C and 1.00 Atmospheres (atm) of pressure. These conditions are known as STP (Standard Temperature and Pressure). Avogadro showed experimentally that one mole of any gas will occupy a volume of 22.4 L at STP. The following conversion factor can be used to find the number of moles, the mass, and even the number of particles in a a gas sample. 22.4 L 1 mol
Molar Volume of Gases Practice • How many moles does 44.8 L of Hydrogen gas at STP represent? • A sample of oxygen gas occupies 6.2 L at STP. How many moles does that represent? • 3. How many liters will 23.50 g of nitrogen occupy at STP? • How many liters will 100 grams of oxygen occupy @ STP? • 5. How many grams of oxygen would be required to occupy 11.2 L at STP?
Volume of Gases Practice 6. A sample of chlorine gas occupies 72.3 L @ STP. How many grams of chlorine gas are present? 7. How many moles of hydrogen gas are present in 162.4 liters @ STP? 8. How many grams of lithium gas would be required to fill a 50 liter container @ STP? 9. A sample of bromine gas occupies 28.3 liters @ STP. How many grams of bromine gas are present? 10. What is the mass of 857 liters of nitrogen gas @ STP?