Nature of Matter Elements Compounds and Mixtures Class 8 MCQ
hardNature of Matter Elements Compounds and Mixtures Class 8 MCQ
Nature of Matter Elements Compounds and Mixtures Class 8 MCQ
Question 1.
Which of the following statements is true about elements?
(a) Elements can be broken down into simpler substances.
(b) Elements are made up of two or more different types of atoms.
(c) Elements are the simplest substances that cannot be broken down further.
(d) Elements have a variable composition.
Answer:
(c) Elements are the simplest substances that cannot be broken down further.
Question 2.
What is a compound?
(a) A substance made of only one type of atom.
(b) A mixture of two or more elements that retain their individual properties.
(c) A substance formed when two or more elements combine chemically in a fixed ratio.
(d) A type of homogeneous mixture.
Answer:
(c) A substance formed when two or more elements combine chemically in a fixed ratio.
Question 3.
Which of the following is an example of a mixture?
(a) Water (H2O)
(b) Oxygen (O2)
(c) Air
(d) Sodium chloride (NaCl)
Answer:
(c) Air
Question 4.
What distinguishes a pure substance from a mixture?
(a) Pure substances have variable composition.
(b) Mixtures consist of only one type of particle.
(c) Pure substances have a uniform and definite composition.
(d) Mixtures cannot be separated into their components.
Answer:
(c) Pure substances have a uniform and definite composition.
Question 5.
When iron reacts with oxygen, what is formed?
(a) Iron oxide (rust)
(b) Iron sulfide
(c) Iron chloride
(d) Iron hydroxide
Answer:
(a) Iron oxide (rust)
Question 6.
Which of the following substances is a compound?
(a) Nitrogen (N)
(b) Gold (Au)
(c) Water (H2O)
(d) Sand
Answer:
(c) Water (H2O)
Case Study
I. The Art of Dhokra
Dhokra art, originating from Bihar and Odisha, exemplifies the use of elements and compounds in crafting beautiful metal figures. This ancient technique involves creating a model from beeswax, which is then encased in clay to form a mould. Once the mould hardens, the wax is melted out, leaving a hollow space that is filled with molten brass or bronze, showcasing the properties of these metal alloys.
Question 1.
What is the primary metal alloy used in Dhokra art?
(a) Copper
(b) Bronze
(c) Silver
(d) Aluminium
Answer:
(b) Bronze
Question 2.
Which of the following statements is true regarding the materials used in Dhokra art?
(a) The wax model reacts chemically with the clay mould.
(b) The components of the mixture retain their individual properties.
(c) Dhokra art is made exclusively from pure elements.
(d) The final product is a mixture of nonmetallic substances.
Answer:
(b) The components of the mixture retain their individual properties.
Question 3.
Dhokra art involves creating a model from ............, which is then encased in clay to form a mould.
Answer:
beeswax
Question 4.
The process of making Dhokra art results in a strong and shiny figure made from ............or .............
Answer:
brass; bronze
Question 5.
Dhokra art is an example of a chemical change where the original materials lose their individual properties. (True/False)
Answer:
False
II. The Mixture of Salad Ingredients
A sprout salad is an excellent example of a non-uniform mixture, where various ingredients like green gram, chickpeas, onions, and tomatoes are combined. Each component retains its individual properties, contributing to the overall flavour and texture of the dish. This mixture is visually distinct, allowing us to identify each ingredient easily, which is a characteristic of non-uniform mixtures.
Question 1.
What type of mixture is a sprout salad, where ingredients like green gram, chickpeas, onions, and tomatoes are combined?
(a) Uniform mixture
(b) Non-uniform mixture
(c) Compound
(d) Solution
Answer:
(b) Non-uniform mixture
Question 2.
In a non-uniform mixture, what happens to the properties of the individual componerits?
(a) They change completely.
(b) They are lost.
(c) They remain the same.
(d) They combine to form a new substance.
Answer:
(c) They remain the same.
Question 3.
A mixture where the different components are not uniformly distributed and can be seen separately is called a ............mixture.
Answer:
non-uniform
Question 4.
In a mixture, the individual substances that make up the mixture are known as its .............
Answer:
components
Question 5.
In a non-uniform mixture, the components are chemically combined and cannot be separated by physical means. (True/False)
Answer:
False