Students can practice the best Class 8 Science MCQ and Nature of Matter Elements Compounds and Mixtures Class 8 Science Curiosity Chapter 8 MCQ Online Test with Answers for exam preparation.
Class 8 Science Chapter 8 Nature of Matter Elements Compounds and Mixtures MCQ
Nature of Matter Elements Compounds and Mixtures MCQ
Class 8 Science Chapter 8 MCQ Online Test
Question 1.
Which of the following processes can be used to separate the different components of a mixture without changing the chemical nature of the substances involved?
(a) Chemical reactions
(b) Physical methods
(c) Electrical methods
(d) None of the above
Answer:
(b) Physical methods
Question 2.
When two or more substances are mixed to form a mixture, what happens to the original properties of those individual substances?
(a) Form new substances
(b) Lose their original properties
(c) Retain their original properties
(d) Always dissolve completely
Answer:
(c) Retain their original properties
Question 3.
A student prepares a sugar solution and then tries to recover the sugar by evaporating the water. This process is an example of (Competency Based Que.)
(a) A compound breaking into elements.
(b) Separation of a mixture physically.
(c) A chemical change.
(d) Formation of a new substance.
Answer:
(b) Separation of a mixture physically.
Question 4.
Out of the following substances listed below, which one is best classified as a mixture?
(a) Water
(b) Air
(c) Hydrogen
(d) Carbon dioxide
Answer:
(b) Air
Question 5.
Which of the following options represents a mixture in which the components are so evenly mixed that the composition appears uniform throughout?
(a) Vegetable salad
(b) Sand and water
(c) Oxygen in nitrogen
(d) Gravel and dust
Answer:
(c) Oxygen in nitrogen
Question 6.
Which one of the following examples best illustrates a mixture in which the components are not evenly distributed and can be easily identified or separated by simple methods?
(a) Alloy of copper and zinc
(b) Sugar dissolved in water
(c) Sand and iron filings
(d) Air in a sealed bottle
Answer:
(c) Sand and iron filings
Question 7.
Bronze is made of copper and tin. If a bronze statue is broken into pieces, it is still
(a) a new compound
(b) an element
(c) a physical uniform mixture
(d) a solution
Answer:
(c) a physical uniform mixture
Question 8.
Lime water is often used in simple chemical tests. It turns milky when exposed to which of the following gases due to a chemical reaction?
(a) Nitrogen
(b) Oxygen
(c) Carbon dioxide
(d) Argon
Answer:
(c) Carbon dioxide
Question 9.
The tiny dust particles that are often seen floating or suspended in the air inside homes or outdoors are considered as
(a) components of air
(b) part of a uniform gas mixture
(c) pollutants
(d) gaseous particles
Answer:
(c) pollutants
Question 10.
Arun conducted electrolysis of water in the lab and collected two different gases in test tubes. When he brought a burning splinter near one gas, it made a ‘pop’ sound. The other gas made the flame glow brighter. What do these observations indicate? (Competency Based Que.)
(a) Both test tubes contain carbon dioxide.
(b) The first gas is hydrogen and the second is oxygen.
(c) The second gas is hydrogen and the first is oxygen.
(d) Both gases are water vapour.
Answer:
(b) The first gas is hydrogen and the second is oxygen.
Question 11.
Suppose water was merely a mixture of hydrogen and oxygen. Which of the following would occur?
(a) Water would extinguish fire.
(b) It would always boil at the same temperature.
(c) It might explode when exposed to flame.
(d) It would dissolve sugar more effectively.
Answer:
(c) It might explode when exposed to flame.
Question 12.
In the laboratory process of passing electricity through watef, a small amount of sulphuric acid is added to the water beforehand. What is the reason for this addition? (Competency Based Que.)
(a) It produces sulphur gas.
(b) It increases conductivity for current flow.
(c) It prevents decomposition of oxygen.
(d) It reduces the boiling point.
Answer:
(b) It increases conductivity for current flow.
Question 13.
An element is a pure substance that is made up of which of the following types of particles?
(a) One
(b) Two
(c) Three
(d) Many
Answer:
(a) One
Question 14.
Which of the substances listed below is classified as a metalloid due to its properties that are intermediate between metals and non-metals?
(a) Boron
(b) Oxygen
(c) Gold
(d) Sulphur
Answer:
(a) Boron
Question 15.
From the given options, which of the substances is best classified as a non-metal in terms of its physical and chemical properties?
(a) Copper
(b) Oxygen
(c) Aluminium
(d) Gold
Answer:
(b) Oxygen
Question 16.
Why is water considered a chemical compound and not a mixture or an element?
(a) It can be separated physically.
(b) It is made of two elements chemically bonded.
(c) It retains properties of hydrogen and oxygen.
(d) It has varying compositions.
Answer:
(b) It is made of two elements chemically bonded.
Question 17.
Why is it not possible to separate common salt (sodium chloride) into sodium and chlorine using physical methods such as filtration or evaporation?
(a) It is a mixture.
(b) It is a pure element.
(c) It is a compound with fixed composition.
(d) It is an alloy.
Answer:
(c) It is a compound with fixed composition.
Question 18.
Jay saw his teacher perform an experiment in which sugar was heated in a test tube. The sugar turned black and water droplets formed inside the tube. Jay concluded that sugar was made up of which elements? (Competency Based Que.)
(a) Hydrogen, oxygen, carbon
(b) Carbon, calcium, sulphur
(c) Oxygen, nitrogen, sodium
(d) Hydrogen, nitrogen, carbon dioxide
Answer:
(a) Hydrogen, oxygen, carbon
Question 19.
A chemist mixes iron filings and sulphur, heats the mix, and afterward it is unaffected by a magnet. This change is
(a) only physical heating
(b) chemical formation of iron sulphide
(c) formation of a non-uniform mixture
(d) melting of sulphur only
Answer:
(b) chemical formation of iron sulphide
Question 20.
Among the following minerals, which one occurs in nature in its native form?
(a) Quartz
(b) Gold
(c) Calcite
(d) Talc
Answer:
(b) Gold
Question 21.
Which one of the minerals listed below is primarily used in the production of cement due to its specific composition and properties?
(a) Talc
(b) Quartz
(c) Graphene
(d) Lead
Answer:
(a) Talc
Question 22.
Talcum powder, commonly used in households and cosmetics, is manufactured from which of the following naturally occurring minerals?
(a) Mica
(b) Talc
(c) Pyroxene
(d) Calcite
Answer:
(b) Talc
Question 23.
Isha visited a construction site and noticed materials like concrete and steel being used. When she asked the engineer, he explained these materials are mainly (Competency Based Que.)
(a) elements and compounds
(b) only pure substances
(c) mixtures, because they are made from more than one material
(d) metals, because they are hard
Answer:
(c) mixtures, because they are made from more than one material
Question 24.
Out of the following substances, which one is best classified as a chemical compound because it is made of elements chemically combined in fixed proportions?
(a) Air
(b) Steel
(c) Water
(d) Soil
Answer:
(c) Water
Question 25.
Alloys such as brass and bronze are widely used in tools and decorative items. How are alloys best classified?
(a) Compound
(b) Element
(c) Uniform mixture
(d) Non-uniform mixture
Answer:
(c) Uniform mixture
Question 26.
Some minerals occur in nature in their pure metallic state without combining with other elements. Which of the following is one such native mineral?
(a) Quartz
(b) Mica
(c) Gold
(d) Calcite
Answer:
(c) Gold
Nature of Matter Elements Compounds and Mixtures Class 8 Assertion Reason Questions
The following questions consist of two statements.
Assertion (A) and Reason (R). Answer the following questions by selecting the appropriate option given below
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Question 1.
Assertion (A) Sugar solution is a uniform mixture.
Reason (R) The solid sugar does not dissolve and settles at the bottom of the container.
Answer:
(c) A is true, but R is false. Sugar dissolves uniformly in water, forming a uniform mixture.
Question 2.
Assertion (A) Air is considered a mixture rather than a compound.
Reason (R) This is because the different gases present in air, such as oxygen, nitrogen, and carbon dioxide, are chemically combined in fixed proportions.
Answer:
(c) A is true, but R is false. Air is a mixture of gases, but its gases are not chemically combined and are not in fixed proportions.
Question 3.
Assertion (A) Alloys are classified as mixtures and not as pure substances.
Reason (R) Alloys are made by physically mixing two or more elements, often metals, without any chemical bonding.
Answer:
(a) Both A and R are true, and R is the correct explanation of A.
Question 4.
Assertion (A) A compound can be separated into its elements by simple physical methods such as filtration or evaporation.
Reason (R) Compounds are chemical mixtures of different elements.
Answer:
(d) A is false, but R is true. Compounds require chemical methods to separate their elements.
Question 5.
Assertion (A) A mixture of iron and sulphur can be separated using a magnet.
Reason (R) This is because iron maintains its magnetic properties even after being mixed with sulphur.
Answer:
(a) Both A and R are true, and R is the correct explanation of A.
Question 6.
Assertion (A) Water is considered a compound.
Reason (R) This is because it can be split into hydrogen and oxygen through the process of passing electricity through water.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 7.
Assertion (A) A magnet can be used to separate iron from a mixture of iron and sulphur.
Reason (R) This is because iron is a magnetic material and responds to a magnetic field, unlike sulphur.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Nature of Matter Elements Compounds and Mixtures Class 8 Case Based MCQ Questions
Question 1.
Riya took three beakers with equal amounts of water. She added salt to the first, sand to the second, and sugar to the third. She stirred all of them for 2 minutes and left them undisturbed. (Competency Based Que.)
(i) Based on the nature of the substances and how they interact with water, which of the materials that Riya added are expected to dissolve completely, forming a clear solution?
(a) Salt and sugar
(b) Sand and sugar
(c) Only sugar
(d) Only sand
Answer:
(a) Salt and sugar
(ii) Upon close observation after the mixtures have settled, which of the three beakers is expected to display a mixture where the components are not uniformly distributed throughout the liquid?
(a) Beaker with salt
(b) Beaker with sand
(c) Beaker with sugar
(d) All three
Answer:
(b) Beaker with sand
(iii) Considering the composition and characteristics of sugar, how would you best classify it among the following categories of substances?
(a) Mixture
(b) Element
(c) Compound
(d) None of these
Answer:
(c) Compound
Question 2.
Arjun performed an experiment in the science lab where he combined iron filings with sulphur powder in a container. He mixed them well and then heated the mixture strongly. After heating, he observed that a new black substance was formed, and it no longer showed the properties of either iron or sulphur. (Competency Based Que.)
(i) What kind of change took place during heating of the mixture?
(a) Physical
(b) No change
(c) Chemical
(d) Reversible
Answer:
(c) Chemical
(ii) The black solid formed after heating, which does not resemble either of the original materials, is best classified as a
(a) mixture
(b) element
(c) compound
(d) alloy
Answer:
(c) compound
(iii) Can the new substance formed be separated by a magnet?
(a) Yes
(b) No
Nature of Matter Elements Compounds and Mixtures Class 8 Fill in the blanks
1. The different components of a mixture, such as solids from liquids or two solids of different sizes, can usually be separated using …………………….. methods.
Answer:
physical
2. When salt dissolves completely in water, the resulting solution is known as a ……………………. mixture.
Answer:
uniform
3. The air we breathe is not a single gas but a combination of various gases such as nitrogen, oxygen, carbon dioxide, etc., and is best described as a …………………….. mixture.
Answer:
uniform
4. Brass, which is a commonly used alloy in electrical fittings and decorative items, is formed by combining two metals: …………………….. and …………………….. .
Answer:
copper, zinc
5. When oil is added to water and the two do not mix uniformly, instead forming separate layers, it results in a ………………………….. and …………………….. mixture.
Answer:
liquid, liquid
6. The smallest unit of a compound is a …………………….. .
Answer:
molecule
7. A substance that is composed of only one type of atom, such as oxygen or gold, and cannot be broken down further by chemical means is known as an …………………….. .
Answer:
element
8. The element silicon, commonly used in electronics and semiconductors, is classified as a …………………….. .
Answer:
metalloid
9. At room temperature, most elements are solids, but there are exceptions. The two elements that exist in liquid form under normal conditions are …………………….. and …………………….. .
Answer:
mercury, bromine
10. To control and clean oil spills in oceans or water bodies, a special …………………….. material is used, which helps to absorb the oil without mixing with water.
Answer:
graphene aerogel
4. A pure substance that consists of only one kind of atom is called an …………………….. .
Answer:
Element
5. Water is a compound made by the chemical combination of the elements …………………….. and …………………….. .
Answer:
hydrogen, oxygen
6. When sugar is heated strongly, it decomposes and leaves behind a black residue known as …………………….. .
Answer:
Carbon
Nature of Matter Elements Compounds and Mixtures Class 8 True or False
1. Mixtures, such as a combination of sand and salt or oil and water, can only be separated by carrying out chemical reactions to break down their components.
Answer:
False, mixtures can be separated by physical methods and not chemical methods.
2. When sugar is added to water and it dissolves completely to form a consistent and evenly mixed liquid, the resulting sugar solution is considered a uniform mixture.
Answer:
True.
3. The air present in our atmosphere is made up mainly of gases like nitrogen and oxygen, and because these gases are chemically bonded, air is classified as a compound.
Answer:
False, air is a mixture, not a compound, and contains more gases than just oxygen and nitrogen.
4. Elements, which are the simplest forms of matter such as hydrogen or carbon, can be broken down further into simpler substances through physical processes like filtration or evaporation.
Answer:
False, elements cannot be broken down by physical or chemical methods as they are the simplest pure substances.
5. Compounds such as water or carbon dioxide are made by combining elements in ratios that can vary depending on how they are formed.
Answer:
False, compounds have a fixed composition with elements combined in definite proportions.
7. Elements are basic substances that cannot be broken down into simpler substances by any chemical method.
Answer:
True
8. Air is a chemical compound made of gases combined in fixed proportions.
Answer:
False
9. Iron retains its magnetic property even after it reacts with sulphur to form iron sulphide.
Answer:
False
Nature of Matter Elements Compounds and Mixtures Class 8 Match the following
Question 1.
Match the Column I with Column II.
| Column I | Column II |
| A. Water | 1. Element |
| B. Sulphur | 2. Uniform mixture |
| C. Air | 3. Compound |
| D. Bronze | 4. Alloy |
| E. Sand in water | 5. Non-uniform mixture |
Answer:
A – 3, B – 1, C – 2, D – 4, E – 5
| Column I | Column II |
| A. Water | 3. Compound |
| B. Sulphur | 1. Element |
| C. Air | 2. Uniform mixture |
| D. Bronze | 4. Alloy |
| E. Sand in water | 5. Non-uniform mixture |
Question 2.
Match the Column I with Column II
| Column I | Column II |
| A. Talc | 1. Used in making cement |
| B. Calcite | 2. Used in talcum powder |
| C. Quartz | 3. Obtained from mineral talc |
| D. Gold | 4. Native metal |
| E. Talcum powder | 5. Used in making glass |
Answer:
A – 2, B – 1, C – 5, D – 4, E – 3
| Column I | Column II |
| A. Talc | 2. Used in talcum powder |
| B. Calcite | 1. Used in making cement |
| C. Quartz | 5. Used in making glass |
| D. Gold | 4. Native metal |
| E. Talcum powder | 3. Obtained from mineral talc |
Question 3.
Match the Column I with Column II.
| Column I | Column II |
| A. Talc | 1. Native element |
| B. Copper | 2. Mixture of metals |
| C. Alloy | 3. Compound mineral |
| D. Sand and water | 4. Non-uniform mixture |
| E. Quartz | 5. Used in talcum powder |
Answer:
A – 5, B – 1, C – 2, D – 4, E – 3
| Column I | Column II |
| A. Talc | 5. Used in talcum powder |
| B. Copper | 1. Native element |
| C. Alloy | 2. Mixture of metals |
| D. Sand and water | 4. Non-uniform mixture |
| E. Quartz | 3. Compound mineral |