Answer:
Precipitation reactions are ones in which at least one of the reactants is in the aqueous phase (i.e., dissolved in water), and a solid forms on the product side which was not present on the reactant side. If all the reactants are solid, then a solid product forming should not be called a precipitate. To be called a precipitate, an insoluble product must form from within solution, either from a solid and solute interacting, or from an interaction strictly between solutes.
Explanation:
Answer:
Normality of KOH = 0.1062 N
<em>Note: The given question is not clearly stated. A related question below is answered and explained;</em>
<em> What is the NORMALITY of a solution of KOH if 45.18 mL are required to neutralize 0.3g of pure oxalic acid H2C2O4 . 2H2O?</em>
Explanation:
Equation of the reaction: 2KOH + H₂C₂O₄.2H₂O --> K₂C₂O₄ + 4H₂O
molar mass 0f KOH = 56 g/mol; molar mass of H₂C₂O₄.2H₂O = 126 g/mol
Number of moles of in 0.3 g of H₂C₂O₄.2H₂O = mass/molar mass
number of moles = 0.3 g / 126 g/mol = 0.0024 moles
From the equation of reaction, 2 moles of KOH are required to neutralize 1 mole of H₂C₂O₄.2H₂O
Number of moles of KOH required to neutralize 0.0024 moles of H₂C₂O₄.2H₂O = 2 * 0.0024 = 0.0048 moles
Molar concentration of 45.18 mL solution of KOH containing 0.0048 moles of KOH = number of moles/volume (L)
molarity of KOH solution = (0.0048/45.18 mL) * (1000 mL/1 L) = 0.1062 mol/L
Normality = n * molarity
where is the number of moles of OH⁻ ions produces from mole of KOH = 1
Normality of KOH = 1 * 0.1062
Normality of KOH = 0.1062 N
Answer:
17. Yes, it represents a chemical reaction. This is because new substances were formed from the original substance.
18. (a) Formation of new substances
(b) Evolution or absorption of large quantity of heat
(c)Change in mass of substances
Explanation:
17. In the model above, molecules of a compound of carbon and hydrogen (molecular formula is C2H6) combines with molecular oxygen (O2) to produce two new substances; a compound composed of two oxygen atoms and one carbon atom (CO2) and another compound composed of two atoms of hydrogen and one atom of oxygen (H2O). Since the new substances formed are completely different from the original substances, it a chemical reaction. Also, a large volume of heat would have been given off.
18. To determine if a chemical reaction has occurred, the following observations can be looked out for.
a. Formation of new substances different entirely from the original substances
b. Evolution or absorption of large quantity of heat during the change. Check whether the vessel containing the substances gets hotter or colder.
c. Change in mass of substances. Since new substances are formed in a chemical reaction, there is usually a significant change in mass of the products and reactants.
