Question

Experiment 6: A Series of Chemical Changes

Experiment A SERIES OF CHEMICAL CHANGES The After Thought ! Cross out the incorrect statements dealing with the notation and interpretation of chemical reactions. In a chemical reaction: - the notation symbolizes the starting substances and the substances produced as a chemical transformation is carried out - the Law of Conservation of Mass requires that the number of atoms of each element cannot change during the process - formulas of the reactants and products must be known and correctly written - the coefficients preceding a formula are interpreted as multipliers of the entire formula comparing coefficients gives the ratio of the masses of the participating substances in grams 2. In a series of chemical changes involving the element nickel, the following reactions are encountered. Write correct formulas for each participating substance including its phase solid (s), liquid (1), gas (g), or solution (aq). Recall that the formula for the naturally occurring form of an element depends on whether it is a metal or a nonmetal Atoms are represented in the symbolism for metals while many nonmetallic elements naturally occur as molecules and need subscripts in their formulas. Using the correct formulas then write and balance cach reaction. Finally identify the class of reaction. a) Two elements, metallic nickel and the reddish liquid bromine, combine to form a yellow-tan solid compound known as nickel (II) bromide. formulas class of reaction Nickel Bromine Nickel (II) bromide Reaction: b) Solid blue-green nickel (II) hydroxide reacts with liquid sulfuric acid (H SO.). They form water and a solution containing green nickel (II) sulfate. formulas class of reaction Nickel (LI) hydroxide Sulfuric acid Nickel (II) sulfate Reaction:

Answer 1

1. Last option is incorrect.

Explanation:

a. The symbols of the reactant and the product are written in balanced chemical equation.

b. Chemical equations are balanced and written according to law of conservation of mass.

c. Formulas of the substance must be written correctly. If written wrong, it will provide false information like wrong reactants used or wrong product being formed or law of conservation of mass is not followed.

d. The coefficient before formula is multiplied with the whole formula. It means that 2 KOH has 2 atoms of K, 2 atoms of O and 2 atoms of H.

e. Coefficients give the molar ratio of the substances and not mass ratio. So, this is incorrect.

2.

2 a). Formula Nickel Nics) Bromine Bra (g) Nickel (II) bromide Nibyz () Class of Reaction = Addition Reaction Reaction = Ni + Br. - Nibra - (s)_ 69) (5) b) Formula Nickel (II) hydroxide Nicol, Sulphuric acid - H₂SO4 Nickel (II) sulphate Nisou Class of Reaction = Acid base Reaction (Neubalisatien Reaction) Reaction = Nilo), + Hy soy → NISO4 + 2H30 c) Formula Nickel (II) carbonate Nickel (II) oxide Nicoz No Carbon dioxide cog Class of Reaction : Decomposition Reaction Reaction: Nico, a Nio & co. Formula Hy drogen Nickel Hg Ni Nickel (II) oxide other product Nio H₂O Class of Reaction: Redox Reaction Reaction: Nio + Hg Ni + H2O