Experiment 5 Pre Lab The substances or solutions shown in a

Experiment 5 - Pre Lab The substances or solutions shown in a-h are to be reacted during the course of this experiment For each: predict chemical formulas for all products, write a balanced chemical reaction (include physical states), and predict what should be observed experimentally (colorless gas evolved, precipitate formed, ammonia smell, etc.). Hint: Refer back to the introductory information. a. Solid smelling salts and aqueous sodium hydroxide (Note: Ammonium hydroxide, NH,OH, does not exist in solution but decomposes to gascous ammonia and water.) Products? Balanced chemical equation? Predicted experimental observations? b. Solid baking soda and aqueous vinegar (acetic acid, HC,H,O, is active component in vinegar) (Note: Carbonic acid, H,CO, does not exist in solution but decomposes to carbon dioxide gas and water.) Products? Balanced chemical equation? Predicted experimental observations? Limestone (CaCO,) and concentrated sulfuric acid c. Products? Balanced chemical equation? Predicted experimental observations? Experiment 5 chemicals in the Home 45

Solution

(a)

Products : Na₂CO₃, NH₃ and H₂O

Balanced chemical equation:

(NH₄)₂CO₃ (s) + 2 NaOH (aq.) ----------> Na₂CO₃ (aq.) + 2 NH₃ (g) + 2 H₂O (l)

Observation: Liberation of pungent smell gas i.e. NH₃

(b)

Products : CH₃COONa, H₂O and CO₂

Balanced equation:

NaHCO₃ (s) + CH₃COOH (aq.) -------------> CH₃COONa (aq.) + H₂O (l) + CO₂ (g)

Observation: Liberation of colourless, odourless gas with quick effervescences that turns lime water to milky and putsoff burning splinter.

(c)

Products: CaSO₄, H₂O and CO₂

Balanced equation:

CaCO₃ (s) + H₂SO₄ (aq.) ------------> CaSO₄ (s) + H₂O (l) + CO₂ (g)

Observation: Liberation of colourless, odourless gas with quick effervescences that turns lime water to milky and putsoff burning splinter.

(d)

Products : HCl and NaHSO₄

Balanced equation:

NaCl (s) + H2SO₄ (aq.) -----------------> HCl (g) + NaHSO₄ (aq.)

Observation:

Colourless gas with pungent smell which gives white dense fumes with the glass rod dipped in NH₄OH solution.

(e)

Products : AgCl and NaNO₃

NaCl (aq.) + AgNO₃ (aq.) ----------> AgCl (s) + NaNO₃ (aq.)

Observation: White curdy precipitate is formed.

(f)

Products : BaSO₄ and MgCl₂

Balancing equation:

MgSO₄.7H₂O (aq.) + BaCl₂ (aq.) -------------> BaSO₄ (s) + MgCl₂ (aq.) + 7 H₂O (l)

Observation: White precipitate is fomred which is insoluble in concentrated HCl also.

(g)

Products : I₂, NaCl and NaOH

Balancing equation:
NaOCl (s) + NaI (aq.) + H₂O (l) -------> I₂ + NaCl + 2 NaOH

Observation: an orange iodine colour is developed.

(h)

Products : AgI and NaNO₃

Balancing equation:

NaI (aq.) + AgNO₃ (aq.) ------------> AgI (s) + NaNO₃ (aq.)

Observation: An yellow precipitate of AgI which is insoluble in NH₄OH solution.