Gravimetric Analysis Quiz

What is the purpose of gravimetric analysis in the context of the provided learning material?

• To measure the volume of a solution

• To determine the identity of an unknown compound by measuring its mass

• To identify the color of a compound

• To measure the temperature of a solution

What is the first step in the gravimetric analysis of a carbonate as described in the document?

• Precipitate the carbonate ions

• Dissolve the soluble compound in water

• Filter and dry the precipitate

• Calculate the number of moles of CaCO3

Which reagent is used to precipitate all of the carbonate ions in the solution?

• NaCl

• H2SO4

• CaCl2

• KNO3

What is the overall reaction for the precipitation reaction described in the document?

• CaCl2(aq) + X2CO3(aq) → CaCO3(s) + 2XCl(aq)

• CaCl2(aq) + CO3^2-(aq) → CaCO3(s)

• X2CO3(aq) → 2X+(aq) + CO3^2-(aq)

• CaCO3(s) → Ca^2+(aq) + CO3^2-(aq)

How do you calculate the number of moles of CaCO3?

• By dividing the mass of the precipitate by the volume of the solution

• By multiplying the mass of the precipitate by the formula mass

• By dividing the mass of the precipitate by the formula mass

• By adding the mass of the precipitate to the formula mass

What is the molar ratio of CaCO3 and X2CO3 in the reaction?

• 2:1

• 1:2

• 1:1

• 3:1

What is the purpose of the procedure described in the document?

• To dissolve an unknown Group I metal carbonate and precipitate all of the dissolved carbonate as calcium carbonate

• To measure the pH of an unknown solution

• To determine the boiling point of an unknown liquid

• To identify the color of an unknown substance

What should you use to transport the crucible to prevent burns?

• Gloves

• Tongs

• Bare hands

• A cloth

What is the first step in the procedure?

• Add 1.00 g of Unknown A or B to the crucible

• Determine the mass of a clean, dry crucible

• Heat the crucible gently

• Place the crucible at a 45° angle in a heating triangle

How should the crucible be heated initially?

• With a constant flame for 10 minutes

• With back-and-forth movement of the flame across the bottom for 3 minutes

• With a high flame for 5 minutes

• With a low flame for 2 minutes