Chemistry Answers

Assign oxidation numbers to all atoms, tell in each which substance is undergoing oxidation and which reduction

PbO2(s)+ Cl(aq)>PbCl2(s)+ O2(g)

The reaction moves in backward direction, when the ratio of the concentrations of the products & the

reactant is:

* Equal to Kc

* Greater than Kc

* Lesser than Kc

* 10-13

The percentage of nickel in the Ni/DMG precipitate is 20.32%. Using the atomic mass of Ni and the formula mass of DMG, derive the percentage.

Solid calcium oxide decomposes into elements

Which of the following correctly determines the mole fraction of 250. g sucrose (MM = 342 g/mol) dissolved in 1000mL of water?

Determine the mass of aluminum chloride formed when 25.0 g of aluminum hydroxide reacts with 50.0 g of hydrogen chloride.

To do: Identify the oxidizing agent and reducing agent in the reactions.

1. 2Na2S2O3+I2→Na2S4O6+2NaI

2. 2FeCl3+H2S→2FeCl2+S+2HCl

3. 3Mg+N2→Mg3N24.AgCN+CN−→[Ag(CN)2]−

To do: From the reactions above, identify the Bronsted-Lowry acid, Bronsted-Lowry base, the conjugate acid, and conjugate base.

No. Bronsted-Lowry acid Bronsted-Lowry base Conjugate acid Conjugate base

1

2

3. Use the changes in oxidation numbers to identify which atoms are oxidized and which are reduced in each reaction:

a. 2H2 (g) + O2(g) →2H2O(l)

b. 2KNO3(s)→2KNO2(s)+ O2(g)

c. NH4NO2(s) →N2(g) + 2H2O(g)

1. For the reaction, H2O(l)⟶H2O(g), calculate ΔG at a) 20oC, b) 100oC and c) 150oC.

2. Calculate the standard-free energy changes for the reaction 2MgO(s) + 2Mg(s) + O2(g) at 25oC .