How to find total pressure of gases

1. combine iron and copper (ii) sulfate solution. (hint: iron will form the iron (iii) ion) fe + cuso4 → 2. combine lead (ii) nitrate and potassium iodide solutions. pb(no3)2+ kl → 3. combine magnesium metal and hydrochloric acid solution. mg + hcl → 4. electrolysis (splitting) of water. h2o → 5. burning magnesium. mg + o2 →

How would the number of moles (n) of o2 change if the atmospheric pressure doubled but all other variables stayed the same

From the choices provided below, list the reagent(s) in order that will react with cyclopentanone to form the compound shown below.