Grade 10 · Science · Chemistry

10th grade Why things dissolve: polarity, electrolytes and nonelectrolytes worksheet

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Why things dissolve: polarity, electrolytes and nonelectrolytes

Grade 10 Science Worksheet - Building Confidence

NameDate

Circle the best answer, or write your answer on the line.

Each unit of table salt (NaCl) splits into 2 ions in water. How many moles of ions come from 0.5 mol of salt, Ari?
Each unit of table salt (NaCl) splits into 2 ions in water. How many moles of ions come from 1.5 mol of salt, Bo?
Each unit of baking soda (NaHCO₃) splits into 2 ions, Na⁺ and HCO₃⁻. How many moles of ions come from 0.25 mol, Kira?
4.
Why don't oil and water mix, Luz?
- Oil melts and floats away
- Water is polar and oil is nonpolar
- Oil dissolves in water once it is stirred long enough
5.
Which dissolves best in water, Milo?
- Cooking oil, once it is warmed
- Sugar
- Candle wax
6.
Salt water lights a conductivity tester; sugar water does not. Why, Noah?
- Salt forms ions; sugar stays as whole molecules
- Salt water is hotter than sugar water
- Sugar forms ions too, but they move too slowly to carry charge
7.
Is sugar water an electrolyte, Pia?
- Yes: sugar splits into charged ions in water
- Yes, if enough sugar is added
- No: sugar stays as whole molecules
8.
Which of these is an electrolyte in water, Ren?
- Baking soda, which forms Na⁺ and HCO₃⁻
- Pure distilled water by itself
- Sugar, which forms sugar ions
9.
In a water molecule, which end is slightly negative, Tala?
- Neither: water has no charged ends
- The oxygen end
- The hydrogen end
10.
Which end of water molecules faces a Cl⁻ ion, Esme?
- Neither end: Cl⁻ stays in its crystal
- The positive hydrogen end
- The negative oxygen end

Why things dissolve: polarity, electrolytes and nonelectrolytes. Every version has 10 questions, and the answer key prints on the second page.

I can explain "like dissolves like": polar water dissolves salt and sugar, but not oil.
I can tell electrolytes (salt and baking soda form ions and conduct) from nonelectrolytes (sugar stays whole).
I can count dissolved particles: 1 mol of NaCl gives 2 mol of ions, and 1 mol of sugar gives 1 mol of molecules.

Standard: none (TX, FL)

polar: Having slightly charged ends, like a water molecule

ion: A charged particle, such as Na⁺ or Cl⁻

electrolyte: A substance that forms ions in water, so the solution conducts

nonelectrolyte: A substance that dissolves as whole molecules, so the solution does not conduct

Your child counted dissolved salt as one particle. Salt splits into two ions, Na⁺ and Cl⁻, so 1 mol gives 2 mol of ions.

Your child thought sugar forms ions. Sugar molecules separate but stay whole, so sugar water doesn't conduct.

Your child pictured salt dissolving as whole units. Water pulls salt apart into Na⁺ and Cl⁻ ions.

What is the most common mistake with why things dissolve: polarity, electrolytes and nonelectrolytes?

Your child counted dissolved salt as one particle. Salt splits into two ions, Na⁺ and Cl⁻, so 1 mol gives 2 mol of ions.

Are these 10th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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