The Amazing World of Solutes Solvents and Solutions Class 8 MCQ
hardThe Amazing World of Solutes Solvents and Solutions Class 8 MCQ
The Amazing World of Solutes Solvents and Solutions Class 8 MCQ
Question 1.
What is a solute in a solution?
(a) The liquid component
(b) The component present in lesser quantity
(c) The component that dissolves
(d) Both (b) and (c)
Answer:
(d) Both (b) and (c)
Question 2.
Which of the following statements is true regarding saturated and unsaturated solutions?
(a) A saturated solution can dissolve more solute at the same temperature.
(b) An unsaturated solution has reached its maximum solubility.
(c) A saturated solution cannot dissolve any more solute at a given temperature.
(d) Both (a) and (b)
Answer:
(c) A saturated solution cannot dissolve any more solute at a given temperature.
Question 3.
How does temperature generally affect the solubility of solids in liquids?
(a) Solubility decreases with an increase in temperature.
(b) Solubility increases with an increase in temperature.
(c) Solubility remains constant regardless of temperature.
(d) Solubility is not affected by temperature.
Answer:
(b) Solubility increases with an increase in temperature.
Question 4.
What happens to the density of a substance when it is heated?
(a) Density increases
(b) Density decreases
(c) Density remains the same
(d) Density becomes zero
Answer:
(b) Density decreases
Question 5.
Why does ice float on water?
(a) Ice is denser than water.
(b) Ice is lighter than water.
(c) Ice has a higher mass than water.
(d) Ice has a lower temperature than water.
Answer:
(b) Ice is lighter than water.
Question 6.
In which state of matter does pressure have the least effect on density?
(a) Gases
(b) Liquids
(c) Solids
(d) All states are equally affected
Answer:
(c) Solids
Question 7.
What is the definition of solubility?
(a) The amount of solute that can be dissolved in a fixed volume of solvent at a particular temperature.
(b) The total volume of a solution.
(c) The mass of the solute in a solution.
(d) The density of the solvent.
Answer:
(a) The amount of solute that can be dissolved in a fixed volume of solvent at a particular temperature.
Question 8.
Which of the following is an example of a solvent?
(a) Sugar in water
(b) Salt in water
(c) Water in a salt solution
(d) Air
Answer:
(c) Water in a salt solution
Question 9.
What is the effect of increasing pressure on the density of gases?
(a) Density decreases
(b) Density increases
(c) Density remains unchanged
(d) Density becomes negative
Answer:
(b) Density increases
Question 10.
Which of the following components is considered a solute in air?
(a) Nitrogen
(b) Oxygen
(c) Argon
(d) Carbon dioxide
Answer:
(b) Oxygen
Case Study
I. The role of temperature in density changes
Temperature significantly affects the density of substances. As temperature increases, particles move apart, causing the volume to expand and density to decrease. This principle explains why hot air rises, creating convection currents that are essential for weather patterns. Understanding this concept is vital in fields such as meteorology and engineering, where temperature control is crucial for various applications.
Question 1.
What happens to the density of a substance as its temperature increases?
(a) Density increases
(b) Density decreases
(c) Density remains the same
(d) Density fluctuates randomly
Answer:
(b) Density decreases
Question 2.
Why does hot air rise in the atmosphere?
(a) It is heavier than cold air
(b) It is less dense than cold air
(c) It has a higher pressure than cold air
(d) It contains more moisture than cold air
Answer:
(b) It is less dense than cold air
Question 3.
As temperature increases, the particles of a substance tend to move apart, causing the volume to ............and the density to ..........
Answer:
increase; decrease
Question 4.
The principle that explains why hot air rises is based on the relationship between temperature and ............, which is crucial for understanding weather patterns.
Answer:
density
Question 5.
Increasing the temperature of a gas will cause its density to increase. (True/False)
Answer:
False
II. Measuring density in everyday life
Density is a practical concept used in everyday life, such as determining whether objects will float or sink in water. For instance, cooking oils often have a density less than that of water, which is why they float. By measuring mass and volume, we can calculate density using the formula Density = [latex]\frac{\text { Mass }}{\text { Volume }}[/latex]. This knowledge helps in various applications, from cooking to material science.
Question 1.
Why do cooking oils float on water?
(a) They are heavier than water.
(b) They have a higher density than water.
(c) They have a lower density than water.
(d) They dissolve in water.
Answer:
(c) They have a lower density than water.
Question 2.
The formula used to calculate density is:
(c) Density = [latex]\frac{\text { Volume }}{\text { Mass }}[/latex]
(b) Density = Mass × Volume
(c) Density =[latex]\frac{\text { Mass }}{\text { Volume }}[/latex]
(d) Density = Volume + Mass
Answer:
(c) Density = [latex]\frac{\text { Mass }}{\text { Volume }}[/latex]
Question 3.
The density of an object can be determined by measuring its ............ and .............
Answer:
mass; volume
Question 4.
If an object has a density greater than that of water, it will ............ in water.
Answer:
sink
Question 5.
The density of a substance is affected by its shape and size. (True/False)
Answer:
False. (The density of a substance is independent of its shape or size.)