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9th grade · Science · Unit 26 of 28

Gases, Solutions, Acids & Bases

Gas laws, dissolving, pH and electron transfer.

What your child practices

Practices how the pressure, volume and temperature of a gas are related, how solutes dissolve and what affects solubility, comparing acids and bases with pH and neutralization, and reactions where electrons move from one substance to another (oxidation and reduction), as in rusting and batteries.

New York State Learning Standards learning standard: HS-PS1-9; HS-PS1-10; HS-PS1-11; HS-PS1-12 · the combined gas law, the properties of solutions, comparing acids and bases, and reactions that transfer electrons

How we explain it

Children can open this short lesson before they practice.

  1. Cooling a gas shrinks it; heating expands it. Squeezing a gas raises its pressure.
  2. Acids have pH below 7, bases above 7. They neutralize each other.
  3. Oxidation is losing electrons; reduction is gaining them.

Example: An atom gains electrons in a reaction. Is it oxidized or reduced? Oxidation is losing electrons. Gaining electrons is reduction. Answer: reduced

Gases, Solutions, Acids & Bases in New York

In the New York State Learning Standards, this is unit 26 of 28 in 9th grade Science, after Waves & Electromagnetic Radiation and before Nuclear Energy & Bond Energy.

Gradelings describes a child's practice on this unit as Beginning, Approaching, Meeting or Exceeding (Four practice steps). That reflects practice, not a report-card mark: the teacher decides the mark.

Source: New York State Education Department (NYSED)

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    At constant temperature, a gas is squeezed into half its volume. Its pressure…

    • doubles
    • halves
    • stays the same
    • drops to zero

  2. Question 2

    A battery makes electricity from…

    • melting
    • electrons transferred in a redox reaction
    • nuclear fusion
    • evaporation

  3. Question 3

    When an acid and a base react, they form…

    • a salt and water
    • a stronger acid
    • only a gas
    • a pure metal

  4. Question 4

    Pure water has a pH of…

    • 1
    • 7
    • 14
    • 0

  5. Question 5

    In salt water, the salt is the…

    • catalyst
    • precipitate
    • solute
    • solvent

  6. Question 6

    A sealed bag of chips puffs up when carried up a mountain because…

    • the chips grow
    • it is hotter on mountains
    • gas shrinks at low pressure
    • outside air pressure is lower, so the gas inside expands

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