Question

A sample of dolomitic limestone containing only CaCO₃ and Mgco₃ . When a 0.2800 gram sample of this dolomitic limestone was decomposed by heating, 75.0 millilitres of CO₂ at 750 mmHg and 20 degrees Celsius were evolved. How many grams of CO₂ were produced?

A) 0.175 g
B) 0.280 g
C) 0.350 g
D) 0.140 g

Answer 1

To determine the grams of CO₂ produced from the limestone sample, the Ideal Gas Law is applied using the given pressure, volume, and temperature. The moles of CO₂ calculated are then converted to grams using its molecular weight.

Step-by-step explanation:

The problem requires using the Ideal Gas Law to find out how many grams of CO₂ were produced from the heated sample of dolomitic limestone. First, we need to convert the volume of CO₂ to standard temperature and pressure (STP) conditions using the equation PV=nRT, where:

• P = pressure in atm (convert 750 mmHg to atm by dividing by 760)
• V = volume in liters (75.0 mL converted to liters by dividing by 1000)
• n = moles of CO₂ (unknown)
• R = ideal gas constant (0.0821 L·atm/K·mol)
• T = temperature in kelvins (convert 20°C to K by adding 273.15)

Once we have calculated the moles of CO₂, we can convert to grams using the molecular weight of CO₂ (44.01 g/mol). The calculated mass of CO₂ is the answer we seek to find.