Solute Examples in Chemistry

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Solute.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

The substance that is dissolved in a solution, typically present in a smaller amount than the solvent.

The thing that 'disappears' when you dissolve it — like sugar dissolving in tea. The sugar is the solute.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Solute asks what the sample is, what property is being used, and whether a new substance is formed.

Common stuck point: Students often know a formula related to solute but skip the recognition step: Am I classifying matter or using properties, state, particle behavior, or mixture evidence to describe a sample? That leads to a correct-looking substitution attached to the wrong chemical model.

Sense of Study hint: Ask: Am I classifying matter or using properties, state, particle behavior, or mixture evidence to describe a sample?

Worked Examples

Example 1

easy
In a solution of sugar dissolved in water, identify the solute and explain its role.

Answer

Solute: sugar (the dissolved substance)\text{Solute: sugar (the dissolved substance)}

First step

1
The solute is sugar — it is the substance being dissolved.

Full solution

  1. 2
    The solute is present in a smaller amount and is dispersed uniformly throughout the solvent.
  2. 3
    The sugar molecules separate and become surrounded by water molecules.
The solute is the minor component of a solution. It can be a solid, liquid, or gas dissolved in the solvent. The solute determines many properties of the solution.

Example 2

medium
In carbonated water, CO2\text{CO}_2 gas is dissolved in water. Identify the solute and solvent, and explain what happens when the bottle is opened.

Example 3

medium
Two students disagree: one says 'a solid is always the solute, a liquid is always the solvent'. Refute this with two concrete examples.

Example 4

hard
A salt mixture contains 4.0g4.0\,\text{g} NaCl (M=58.5M=58.5) and 4.0g4.0\,\text{g} KCl (M=74.55M=74.55) dissolved together in water to 200mL200\,\text{mL}. Compute total Cl\text{Cl}^- molar concentration.

Example 5

challenge
In rubbing alcohol (70%70\% IPA, 30%30\% water), a chemist needs to identify which substance has the higher molarity. Use molar masses (MIPA=60.10g/molM_{\text{IPA}} = 60.10\,\text{g/mol}, MH2O=18.02g/molM_{\text{H}_2\text{O}} = 18.02\,\text{g/mol}) and assume density 0.875g/mL0.875\,\text{g/mL} for the solution.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
In a saline solution (salt water), what is the solute?

Example 2

hard
At 20°C20°\text{C}, the maximum solubility of NaCl\text{NaCl} in water is 36 g36 \text{ g} per 100 mL100 \text{ mL}. If a student adds 50 g50 \text{ g} of NaCl\text{NaCl} to 100 mL100 \text{ mL} of water at 20°C20°\text{C}, what happens? Calculate how much solute dissolves and how much remains undissolved.

Example 3

easy
In salt water, which component is the solute?

Example 4

easy
In sugar dissolved in tea, what is the solute?

Example 5

easy
In carbonated soda, CO2CO_2 gas is dissolved in water. What is the solute?

Example 6

easy
A small amount of food coloring is added to a large glass of water. What is the solute?

Example 7

easy
In a copper-zinc alloy with mostly copper, which is the solute?

Example 8

easy
Ethanol is mixed into water as a small additive. Which is the solute?

Example 9

easy
In iced tea sweetened with honey, what is the solute?

Example 10

easy
In a solution, which component is usually present in the smaller amount?

Example 11

medium
A solution is 5 g salt dissolved in 95 g water. Identify the solute and explain using the amount criterion.

Example 12

medium
In a mixture of 90 g ethanol and 10 g water, which is the solute? Explain why state does not decide this.

Example 13

medium
Sugar appears to 'vanish' when stirred into water. Where did the sugar go, and is it still the solute?

Example 14

medium
A nurse prepares a saline drip: NaClNaCl dissolved in sterile water. Identify the solute and one reason its concentration matters.

Example 15

medium
In brass (mostly copper, some zinc), identify the solute and explain why this is a solid solution.

Example 16

medium
Two solutions: (A) 1 spoon sugar in 1 cup water, (B) 3 spoons sugar in 1 cup water. Which has more solute, and what property differs?

Example 17

medium
Why can a gas like oxygen be called a solute when it is dissolved in lake water?

Example 18

challenge
A solution contains 20 g of dissolved KNO3KNO_3 in 80 g of water. State the solute, compute the mass percent of the solute, and interpret it.

Example 19

challenge
Explain why, in a 30 g water + 70 g ethanol mixture, calling water the solute is correct, and connect this to the 'like dissolves like' idea.

Example 20

challenge
A drink is made by dissolving 12 g sugar and 3 g salt in 185 g water. Identify all solutes, the solvent, and the total solution mass.

Example 21

medium
In a soda, both CO2CO_2 gas and sugar are dissolved in water. List the solutes and the solvent.

Example 22

medium
As you keep adding sugar to water until no more dissolves, what is happening to the solute, and what is this state called?

Example 23

easy
In ocean water, the main dissolved substance is sodium chloride. Identify the solute.

Example 24

easy
A cup of tea contains tea leaves' extract, sugar, and a small amount of milk dissolved in water. Name three solutes.

Example 25

easy
In bronze (mostly copper with about 12%12\% tin), what is the solute?

Example 26

easy
In humid air, water vapor is dissolved in nitrogen/oxygen gas. What is the solute?

Example 27

easy
A doctor prescribes a 0.9%0.9\% saline IV. The dissolved substance is salt; the rest is water. Identify the solute.

Example 28

medium
A juice contains 14g14\,\text{g} of sugar, 0.5g0.5\,\text{g} of vitamin C powder, and 0.1g0.1\,\text{g} of natural flavor dissolved in 185.4g185.4\,\text{g} of water. List solutes, the solvent, and total mass.

Example 29

medium
You add 25g25\,\text{g} of KNO3\text{KNO}_3 to 100g100\,\text{g} water; solubility at this temperature is 32g/100g32\,\text{g}/100\,\text{g}. Identify the solute and state whether the solute fully dissolves.

Example 30

medium
A laboratory bottle is labeled '2.0M2.0\,\text{M} NaOH(aq)'. What is the solute, and what does the label tell you about its concentration?

Example 31

medium
In sterling silver (92.5%92.5\% Ag, 7.5%7.5\% Cu), identify the solute and the resulting solution type.

Example 32

medium
In a 30.0g30.0\,\text{g} sugar solution containing 4.5g4.5\,\text{g} sugar, compute the mass percent of the solute.

Example 33

medium
Sea water averages about 3.5%3.5\% NaCl by mass. In 1.0kg1.0\,\text{kg} of sea water, how much solute is present?

Example 34

medium
A student dissolves 5.85g5.85\,\text{g} NaCl in enough water to make 250mL250\,\text{mL} of solution. Identify the solute and compute its molarity. (MNaCl=58.5g/molM_{\text{NaCl}} = 58.5\,\text{g/mol})

Example 35

hard
A bottle is labeled '70%70\% isopropyl alcohol (IPA), 30%30\% water'. A common claim is 'IPA is the solute because it's the active ingredient'. Critique this claim.

Example 36

hard
15.0g15.0\,\text{g} of glucose (M=180.0g/molM = 180.0\,\text{g/mol}) and 5.85g5.85\,\text{g} NaCl (M=58.5g/molM = 58.5\,\text{g/mol}) are dissolved in 500mL500\,\text{mL} water. List the solutes and find each one's molar concentration.

Example 37

hard
A 250mL250\,\text{mL} solution contains 0.50M0.50\,\text{M} KCl. How many grams of solute were dissolved? (MKCl=74.55g/molM_{\text{KCl}} = 74.55\,\text{g/mol})

Example 38

hard
A solution is prepared by mixing 50mL50\,\text{mL} of 1.0M1.0\,\text{M} NaCl with 50mL50\,\text{mL} water. Identify the solute and find its final concentration.

Example 39

hard
A 100g100\,\text{g} saturated NaCl solution at 20°C20°\text{C} contains 26.5%26.5\% NaCl. Find the mass of solute that crystallizes if the solution is evaporated until 40g40\,\text{g} of water remains, with no more dissolving allowed.

Example 40

hard
A vinegar bottle is 5%5\% acetic acid by mass. A 250g250\,\text{g} bottle holds how much solute (acetic acid)? In moles, how much? (M=60.05g/molM = 60.05\,\text{g/mol})

Example 41

challenge
A 0.100M0.100\,\text{M} AgNO3_3 solution (250mL250\,\text{mL}) is mixed with a 0.100M0.100\,\text{M} NaCl solution (250mL250\,\text{mL}). Identify the original solutes, then describe what happens to the Ag+^+ and Cl^- after mixing.

Background Knowledge

These ideas may be useful before you work through the harder examples.

homogeneous mixture