What mass of sodium hydroxide (NaOH, molar mass = 40.0 g/mol) is needed to make 100.0 mL of a 0.125 M NaOH solution?

For the galvanic cell at 298 K: 2Cr(s) + 3Ni2+(aq) → 2Cr3+(aq) + 3Ni(s)   Eocell = 0.51 V What is the measured cell potential (Ecell), when = 1.0 M and = 0.01 M?  

What is the molar solubility of a saturated solution of magnesium hydroxide, Mg(OH)2, in water? The Ksp of Mg(OH)2 is 1.2×10–11.

A 1.0 L flask is filled with NO and O2 initially, and after the reaction establishes equilibrium, the flask is found to contain 0.0018 mol NO, 0.0012 mol O2 and 0.78 mol NO2. What is the value of the equilibrium constant, Kc, at this temperature? 2NO(g) + O2(g) ⇌ 2NO2(g)

Which solution will have the highest concentration of the hydrogen ion? The Ka of propanoic acid, C2H5COOH, is 1.4×10–5 and benzoic acid, C6H5COOH, is 6.5×10–5.

The density of a 3.539 M HNO3 aqueous solution is 1.150 g/mL at 20 oC. What is the molal concentration? The molar mass of HNO3 is 63.02 g/mol.

The decomposition of hydrogen peroxide, H2O2(aq), is proposed to follow a reaction mechanism of: Step 1: H2O2(aq) + Br–(aq) → H2O(l) + BrO–(aq) Step 2: BrO–(aq) + H2O2(aq) → H2O(l) + O2(g) + Br–(aq) What is the catalyst, and what is the effect of having a catalyst present?

For the process: O2(g) → 2O(g)   ΔH° = 498 kJ/mol What would be the predicted sign of ΔS°rxn and the conditions under which this reaction would be spontaneous?

Which gas, helium or argon, effuses faster under the same conditions and by how much?          

How many protons, neutrons, and electrons are in one atom of ?