State of Matter

11.A pure substance which contains only one type of atoms is called:
 
A. an element
 
B. a compound
 
C. a solid
 
D. a liquid
 
Option “A” is correct.
Since, every atom is also known as element.
Hence a pure substance containing only one type of atom is called an element, and containing only one type of molecule is called a compound.
12.A substance formed by combining two or more than two pure substances in a definite proportion is called
 
A. Element
 
B. compound
 
C. mixture
 
D. Solid
 
Option “B” is correct.
13._____  is formed by mixing two or more pure substances in any proportion
 
A. Element
 
B. compound
 
C. mixture
 
D. gas
 
Option “C” is correct.
A mixture is a combination of two or more pure substances in which each pure substance retains its individual chemical properties. Mixtures can be composed of solid, liquids or gases. There can be classified as homogeneous and heterogeneous.
14.Elements that have the properties of metals and non-metals are called
 
A. ideal metal
 
B. metalloid
 
C. alloy
 
D. metal stool
 
Option “B” is correct.
Some elements show the properties of both metals and non- metals like silicon, germanium etc falls under the category of the metalloid.
15.Which metal is a bad conductor of electricity
 
A. tin
 
B. copper
 
C. tungsten
 
D. nickel
 
Option “C” is correct.
Tungsten is the poorest conductor of electricity.
16.Which non-metal has metallic luster?
 
A. graphite
 
B. iodine
 
C. both of the above
 
D. None of these
 
Option “C” is correct.
Among the given options graphite, which is a crystalline form of carbon and iodine are the two non-metals that have shiny and lustrous surface.
17.Which of the following is a metalloid
 
A. arsenic
 
B. antimony
 
C. bismuth
 
D. all of these
 
Option “D” is correct.
The six commonly recognised metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium.
18.Which of the following is a compound
 
A. Air
 
B. Mercury
 
C. Ozone
 
D. Ammonia
 
Option “D” is correct.
Ammonia, NH3, is a chemical compound composed of one nitrogen atom and three hydrogen atoms. Ammonia is a colorless gas that is lighter than air, and can be easily liquefied. Ammonia is a compound normally encountered as a gas and has a strong odor.
19.Water is a compound because
 
A. It is found in all the three forms of solid, liquid and gas.
 
B. it contains hydrogen and oxygen
 
C. It consists of two different elements joined by chemical bonds
 
D. It can be broken down into two simpler substances by chemical means
 
Option “C” is correct.
Water is a compound because it is made up of water molecules. There is no such thing as water atoms. Water molecules are made of hydrogen and oxygen atoms, in the definite proportion of two hydrogens for one oxygen.
20.Match List-I with List-II and select the correct answer from the code given below the Lists : List-I (Material) A. Diamond B. Marble C. Rail (Sand) D. Ruby List-II (Element ) 1. Calcium 2. Silicon 3. Aluminum 4. Carbon
 
A. A → 1, B → 2, C → 3, D → 4
 
B. A → 4, B → 1, C → 2, D → 3
 
C. A → 4, B → 3, C → 2, D → 1
 
D. A → 3, B → 4, C → 1, D → 2
 
Option”B” is correct

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