1. 25 cm3 of a solution of 0.1 moldm-3 NaOH reacts with 50 cm3 of a solution of hydrochloric acid. What is the molarity of the acid? 2. 25.0 cm3 of a 0.10 moldm-3 solution of sodium hydroxide was titrated against a solution of hydrochloric acid of unknown concentration.
CHE 111 Laboratory 3 Hydrates Introduction Hydrates Water molecules combine with the molecules of certain substances, forming loose chemical combinations called hydrates. An example of a hydrate is MgSO4•7H2O. This formula means 7 water molecules are loosely attached to a magnesium sulfate molecule. Other examples of hydrates are Na2SO4•10H2O and Ba(OH)2•8H2O. When the hydrate is heated, it easily loses water molecules attached and becomes an anhydrous salt.
A) double; covalent B) double; ionic C) single; covalent D) single; ionic E) triple; covalent 3. Which property could describe a covalent compound? A) It conducts electricity when melted. B) Has a low boiling point C) It is composed of a non-metal and a metal. D) It conducts electricity when dissolved in water.
of moles of Cu2O = no. of moles of O = 0.00875 mol (critical step) mass of Cu2O = 0.00875 x (63.5 x 2 + 16.0) = 1.25125 g percentage by mass of Cu2O = (1.25125 )/2.02 x 100 % = 61.9 % Common mistake: no. of moles of (Al2O3 + Cu2O) = Comment: no. of moles = Example 2 0.144 g of a binary compound of aluminium and carbon reacts with an excess of water to produce a gas. This gas burns completely in oxygen to form water and 72 cm3 of carbon dioxide only.
A) gas B) solid C) salts D) ice E) liquid 3. A small amount of salt dissolved in water is an example of a __________. A) compound B) solid C) heterogeneous mixture D) pure substance E) homogeneous mixture 4. Which of the following is an illustration of the law of constant composition? A) Water is 11% hydrogen and 89% oxygen by mass.
An aqueous solution of ammonium sulfate is allowed to react with an aqueous solution of lead(II) nitrate. Identify the solid in the balanced equation. A) (NH4 )2 SO4 B) Pb(NO3 )2 C) PbSO4 D) NH4 NO3 E) There is no solid formed when the two solutions are mixed. ____ 11. An aqueous solution of sodium carbonate is reacted with an aqueous solution of calcium chloride.
A. II only B. III only C. II and III D. I only 6. A hydrate is a A. buffer solution of water B. compound in which hydrogen is combined with an element less electronegative than itself C. compound containing a definite number of water molecules in its chemical composition D. salt containing the hydroxyl radical 7. Two moles of hydrogen react with 1 mole of oxygen to produce which of the following? A. 1 mole of water B.
The chemical reaction used to find this constant is as follows: MgC2O4 (s) ↔Mg(aq)2++ C2O4 (aq)2- Kc= Mg2+[C2O42-][MgC2O4] Ksp=Mg2+[C2O42-] The solid salt magnesium oxalate is prepared through the following precipitation reaction: Mg(SO4)(aq)+NaC2O4 (aq) → MgC2O4 (s)+NaSO4 (aq) Next, the concentration of the Mg2+ and C2O42- ions is found through a redox titration. This redox titration uses a standardized potassium permanganate solution. The potassium permanganate solution is standardized by titrating it with samples of iron(II)ammonium sulfate hexahydrate . The end point is reached when the solution has turned light purple which is a result of excess amounts of MNO4-. This reaction can be summed up using the following formula: 5Fe2++8H++MnO4- →5Fe3++Mn2++4H2O After standardization, the potassium permanganate solution is then titrated with 3 different magnesium oxalate solutions.
Writing balanced molecular equations and net ionic equations. Acid-base reactions. Oxidation-Reduction reactions. Assigning oxidation numbers to elements in compounds and ions. Molarities of solutions and molar concentrations of ions.
high melting point, hard, brittle, slightly soluble in water, conductor of electricity when melted or in solution Molecular solid - crystalline solid that has molecules arranged in a particular configuration. low melting point, generally insoluble in water, nonconductor of electricity. Metallic solid - crystalline solid that has atoms of metals arranged in a definite pattern. low to high melting point, malleable, ductile, conductor of electricity, insoluble in most solvents. Lesson 13.6 Changes of physical state: * necessary to draw a temperature-energy graph to see the change in temperature with a constant application of heat Heat of fusion - the amount of heat required to melt 1.00 g of substance.