1. Calcium Content of Tums CHEM 212 Exp. 10

2. Characteristics of Gases, cont. In order to fully describe a gas, four quantities are needed: 1.Pressure (P) – in Pa (SI unit), atm, mm Hg, torr 2.Volume (V) – in L 3.Temperature (T) – in K 4.Quantity of gas (n) – in moles

3. 10.2 Pressure P = F/A Measuring pressure: – Atmospheric pressure – measured with a barometer. (p. 396) – Gas pressure in a container – measured with a manometer. (p. 397) Standard atmospheric pressure = 1 atm 1 atm = 760 torr = 760 mm Hg 1 atm = 760 torr = 760 mm Hg = 29.92 in Hg = 101,325 Pa = 14.70 psi = 1013.25 mBar

4. 10.4 The Ideal-Gas Equation PV = nRT P – pressure in atm (additive) V – volume in L n – mol (additive) R – gas constant (Table 10.2, p. 402) = 0.08206 L·atm/mol·K = 8.314 J/mol·K (101.3 J = 1 L·atm) T – temperature in K

5. CaCO 3 (s) + 2 HCl(aq) → CaCl 2 (aq) + H 2 O(l) + CO 2 (g)

6. 10.6 Collection of a gas over water Total gas collected = product gas + water vapor P total = P gas + P water, and P gas = P total - P water