SK015 PRE LAB 3 DETERMINATION MOLAR MASS OF A METAL

What is the purpose of back-titration in this experiment?

• To speed up the reaction of the metal with acid

• To determine the volume of HCl directly

• To find the amount of unreacted acid after the metal reacts

• To prevent the metal from reacting with water

Which of the following is an alkaline earth metal?

• Sodium (Na)

• Magnesium (Mg)

• Potassium (K)

• Iron (Fe)

What is the balanced chemical equation between magnesium and hydrochloric acid?

• Mg + HCl → MgCl + H

• Mg + 2HCl → MgCl₂ + H₂

• Mg + HCl → MgCl₂ + H₂

• Mg + H₂O → MgOH + H₂

In the experiment, an alkaline earth metal reacts with hydrochloric acid to produce…..

• A salt and hydrogen gas

• A salt and oxygen

• A base and hydrogen gas

• A base and water

What is the oxidation number of calcium in CaCl₂?

• 0

• +1

• +2

• -1

What is the function of NaOH in this experiment?

• Titrate excess HCl

• React with metal

• Act as a catalyst

• Form a precipitate

Which of the following is a characteristic of back titration?

• Excess base is added to the analyte

• It involves direct titration with an indicator

• It does not require a balanced chemical equation

• Excess acid is added, and the unreacted portion is titrated

In this experiment, why is excess HCl added to the metal?

• To increase the rate of reaction

• To ensure complete reaction of the metal

• To neutralize the metal oxide

• To measure the pH change

If 1 mole of M reacts with 2 moles of HCl, what is the mole ratio of metal M to hydrochloric acid in the reaction?

• 1:1

• 1:2

• 2:1

• 1:3

Why is it important to know the exact volume of NaOH used in the titration?

• To calculate the strength of HCl

• To determine the amount of precipitate formed

• To find the melting point of the metal

• To calculate the number of moles of unreacted HCl