SAT Chemistry questions

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1

Hello, I’m having a bit of trouble with a few SAT Chemistry questions.
If you know the answer to the question, can you please explain it.

  1. Most of the alpha particles directed at a thin sheet of gold foil pass through it, while only a few particles are widely deflected BECAUSE the nucleus occupies a very small portion of the volume of the gold atom.

  2. A solution of sodium phosphate,Na3PO4, in water is basic BECAUSE PO43- is a Bronsted Base that accepts H+ in an aqueous solutions to form HPO42- and OH-.

  3. An aqueous solution of table salt, NaCl, conducts electricity BECAUSE NaCl is readily ionized in water to form the NaCl+ ion plus an electron.

2

  1. True. The nucleus of an atom is positively charged and an alpha particle also has a positive charge. Remember like repels like, so the atom’s nucleus and the alpha particle should repel each other when they get close enough. Since few particles were repelled, there was a low chance of the alpha particles coming close to the Au atom’s nucleus.

  2. True. It is a base because it accepts an H+ ion from the H2O molecules (thus producing OH-). While it does form some HPO42-, OH- is a much stronger base than HPO42- is an acid, so the solution is basic.

  3. True/False. This first part is true but the second is not. NaCl easily ionizes into water but does not form NaCl+ and an electron. It forms Na+ and Cl-.