ismétlés

What is the definition of a solute in a chemical solution?

• The substance that dissolves the solute

• The substance in the smallest amount that is dissolved in the solvent

• The substance that forms the solution with the solvent

• The liquid portion of the solution

Answer explanation

The solute is the component of a solution that is present in the smaller amount and gets dissolved in the solvent to form the solution.

Which of the following is an example of a homogeneous solution?

• Sand and water mixture

• Oil and vinegar mixture

• Saltwater solution

• Carbonated beverage

Answer explanation

A homogeneous solution has a uniform composition throughout, and saltwater solution is an example where salt (solute) is uniformly dissolved in water (solvent).

What is the process called when a solid directly changes into a gas without becoming a liquid?

• Evaporation

• Sublimation

• Condensation

• Freezing

Answer explanation

Sublimation is the process where a solid substance transforms directly into a gaseous state without passing through the liquid phase.

What is the molarity of a solution containing 0.5 moles of solute in 1 liter of solvent?

• 0.5 M

• 1 M

• 0,2 M

• 2 M

Answer explanation

Molarity (M) is calculated by dividing the moles of solute by the volume of the solution in liters. In this case, 0.5 moles of solute in 1 liter of solvent gives a molarity of 1 M.

Which of the following is a colligative property of a solution?

• Color

• Density

• Boiling point elevation

• pH

Answer explanation

Colligative properties of a solution depend on the number of solute particles present and include boiling point elevation, freezing point depression, and osmotic pressure.

What is the pH value of a neutral solution?

• 0

• 7

• 14

• 1

Answer explanation

The pH scale ranges from 0 to 14, where 7 is considered neutral. Values below 7 are acidic, while values above 7 are basic.

Which of the following is an example of an exothermic reaction?

• Photosynthesis

• Rusting of iron

• Combustion of gasoline

• Electrolysis of water

Answer explanation

An exothermic reaction releases heat energy. The combustion of gasoline is an example of an exothermic reaction where heat is produced.

What is the purpose of a catalyst in a chemical reaction?

• To speed up the reaction

• To slow down the reaction

• To increase the solubility of the reactants

• To change the colour of the solution

Answer explanation

A catalyst is a substance that increases the rate of a chemical reaction without being consumed itself. It lowers the activation energy, allowing the reaction to occur more quickly.

Which of the following is an example of a saturated solution?

• Dissolving sugar in hot water until no more sugar can dissolve

• Mixing oil and water together

• Dissolving a solid in a gas

• Adding more solute to a solution until it becomes cloudy

Answer explanation

A saturated solution is one where the solvent has dissolved the maximum amount of solute possible at a given temperature. Any additional solute will not dissolve.

What is the chemical formula for water?

• H2O

• CO2

• NaCl

• C6H12O6

Answer explanation

The chemical formula for water is H2O, which represents two hydrogen atoms bonded to one oxygen atom.