2. What is the pH of a solution containing a hydrogen ion concentration of 3.0x10-4M? а

Fe has three major isotopes, with masses of 54, 56, and 57. Fill in the following information for each isotope:

Mendeleev organized his periodic table of the elements by atomic mass; we now order elements on the periodic table by atomic number. Why is the atomic number a better choice than atomic mass for organizing the Periodic Table?

Objective: Organize your thoughts and the main points of your research for your final presentation

The natural abundance of the three stable isotopes of magnesium are 78.99% magnesium- 24 (23.98504 amu), 10% magnesium-25 (24.9858 amu), and 11.01% magnesium-26 (25.9829 amu). Calculate the atomic weight or atomic mass of magnesium and compare your value with that given in the Periodic Table. (Note: The units of atomic weight are atomic mass units (amu).

a. Limestone (CaCO3) is decomposed by heating to quicklime (CaO) and carbon dioxide. Give the balanced equation for the reaction and calculate the mass of quicklime produced from 1.000 kg of limestone. b. An iron (Fe) bar weighed 664 g. After the bar had been standing in moist air for a month, exactly one-eighth of the iron turned to rust (Fe₂O3) as shown in the reaction below. Calculate the final total mass of the iron bar and rust. Molar mass of Fe₂O₂ is 159.7 g/mol. 4 Fe+30₂ - 2Fe₂O₂ c. In a laboratory, a student was doing a homogeneous reaction. She placed 0.300 mol of PCI; (g) and 0.140 mole of Cl₂ (g) in 1.5 L of water at 250°C. After the following reaction came to equilibrium, it was found that the equilibrium concentrations of PCI2, PC15, Cl₂ are 0.170 M, 0.078 M, 0.025 M respectively. P Cl₂(g) + Cl(g) =PC15(9) What were the initial concentration of the reactants? (Hint - Unit of concentration is M or mol/L) Write the equilibrium constant expression for this reaction. What is the value of Kc for this reaction at this temperature? Although the forms of the equilibrium constant and the reaction quotient appear similar, they differ in one crucial aspect. What is the difference between the two? How will the amount of PCI; (g) present in an equilibrium mixture of those gases be affected by the following? Explain your answer. (a) Adding PCl₂ (g) (b) Increasing the volume to the reaction vessel (c) Adding catalyst

5. Ice is less dense than liquid H-bonding produces an _________structure when frozen. Question: Why is this significant to living systems like lake or ponds? Answer: lakes or ponds do not freeze_______,THUS_____ underlying water and its organisms.

2. Using your knowledge of types of reactions, predict the reaction type that will occur for Reactions A through G.

How many grams are equal to 9.34 moles of nitrogen gas? (N₂)

02 Question (4 points) 1st attempt Part 1 (2 points) I've discovered a new material! Its entropy of vaporization is 322.5 J/mol-K and its enthalpy of vaporization is 580 kJ/mol. Which of the following is TRUE? Choose one: O Vaporization always decreases entropy of a system. O Vaporization always increases entropy of a system. O Vaporization at high temperatures increases entropy of a system, but at low temperatures decreases entropy. O Vaporization at high temperatures decreases entropy of a system, but at low temperatures increases entropy. Part 2 (2 points) di See Periodic Table What is the vaporization point, in K, for this material? K