CHE 117 Practice Problems for Final

Lewis dot structures

Draw the Lewis dot structure for each of the following compounds. Predict the compounds shape. Determine whether the compound will be polar or nonpolar

NH₄⁺      tetrahedral, nonpolar

CH₂O      trigonal planar, polar

AlCl₃      trigonal planar, nonpolar

Electron configurations

Write the electron configuration for each of the following elements.

N,       1s²2s²2p³

Cl,       1s²2s²2p⁶3s²3p⁵

Zn,       1s²2s²2p⁶3s²3p⁶4s²3d¹⁰

More pH problems

Determine the pH or [H⁺] for each of the following solutions.

[HCl] = 2.35 x 10^-4,       3.629

[HNO₃] = 0.000452,       2.344

[KOH] = 4.65 x 10^-4,       10.667

sodium carbonate with [^-OH] = 5.6 x 10^-5,       9.748

potassium acetate with pH = 10.52,       3.02 x 10^-11

benzoic acid with pH = 5.36,       4.36 x 10^-6

More limiting reagent problems

Consider the following reaction. If you have 56.43 grams of carbon monoxide (CO) and 35.73 grams of hydrogen (H₂), how many grams of methanol can form?

CO      +      2 H₂            CH₃OH
64.49 grams of CH₃OH can form. CO is the limiting reagent.

Consider the following reaction. If you have 46.5 grams of zinc oxide (ZnO) and 36.5 grams of coke (C), how much zinc (Zn) can you form?

ZnO      +      C            Zn      +      CO
37.4 grams of Zn can form. ZnO is the limiting reagent.

Consider the following reaction. If you have 35.4 grams of bromine (Br₂) and 76.3 grams of aluminum (Al), how much aluminum bromide (AlBr₃) can you form?

2 Al      +      3 Br₂            2 AlBr₃
39.39 grams of AlBr₃. Br₂ is the limiting reagent.