9th Grade > Chemistry
IS MATTER AROUND US PURE MCQs
Total Questions : 50
| Page 5 of 5 pages
Answer: Option A. ->
True
:
A
:
A
Air is a mixture and not a compound because:
1) Air does not have a fixed composition.
2) The components of air can be separated by a physical method such as fractional distillation of liquid air.
3) We can prepare air artificially by mixing the various components of air in the same proportions in which they occur at a place.
Answer: Option A. ->
Used to separate salt from water
:
B, C, and D
Centrifugation is used to separate the components of mixtures using the principle of density difference. When the mixture is spun rapidly in a centrifuge tube, the denser particles are thrown away from the centre and stick to the walls of the centrifuge tube and the lighter particles align themselves towards the centre. It is used in:
∙ Diagnostic laboratories for blood tests (to separate the different components of blood).
∙ Dairies to separate butter from cream.
∙ Washing machines to squeeze out water from wet clothes.
:
B, C, and D
Centrifugation is used to separate the components of mixtures using the principle of density difference. When the mixture is spun rapidly in a centrifuge tube, the denser particles are thrown away from the centre and stick to the walls of the centrifuge tube and the lighter particles align themselves towards the centre. It is used in:
∙ Diagnostic laboratories for blood tests (to separate the different components of blood).
∙ Dairies to separate butter from cream.
∙ Washing machines to squeeze out water from wet clothes.
Answer: Option A. ->
They always have two phases.
:
A
A colloid is a heterogeneous mixture in which the particles of the dispersed phase are distributed non-uniformly in the dispersion medium.
A colloidal solution is always made up of two phases- dispersion medium and dispersed phase. The two phases of a colloid can be a solid, a liquid or a gas. However, its constituent particles are very small in size. Hence, it cannot be separated by filtration.
Examples of colloids are blood, paint, etc.
:
A
A colloid is a heterogeneous mixture in which the particles of the dispersed phase are distributed non-uniformly in the dispersion medium.
A colloidal solution is always made up of two phases- dispersion medium and dispersed phase. The two phases of a colloid can be a solid, a liquid or a gas. However, its constituent particles are very small in size. Hence, it cannot be separated by filtration.
Examples of colloids are blood, paint, etc.
Answer: Option C. ->
Distillation
:
C
Miscible liquids are those liquids which completely mix with each other and form a uniform mixture. Distillation is used for separating two miscible liquids that have a considerable difference in their boiling points.
When the mixture is heated, the liquid with a lower boiling point vaporises first and the vapours can be collected. The vapours are then condensed to get the liquid back in a separate flask. The other liquid doesn't vaporise at this temperature as it has a higher boiling point and stays liquid. So, the liquids are now separated.
:
C
Miscible liquids are those liquids which completely mix with each other and form a uniform mixture. Distillation is used for separating two miscible liquids that have a considerable difference in their boiling points.
When the mixture is heated, the liquid with a lower boiling point vaporises first and the vapours can be collected. The vapours are then condensed to get the liquid back in a separate flask. The other liquid doesn't vaporise at this temperature as it has a higher boiling point and stays liquid. So, the liquids are now separated.
Answer: Option C. ->
sublimation
:
C
Sublimation separates a mixture of solids in which one solid undergoes sublimation. In other words, it changes directly to vapour on heating, without going through the liquid state.
Iodine is a solid that sublimes. When a mixture of iodine and sand is heated in a beaker, the iodine changes from solid to
vapour directly.
These vapours of iodine can be obtained by cooling. They will change back to solid directly.
:
C
Sublimation separates a mixture of solids in which one solid undergoes sublimation. In other words, it changes directly to vapour on heating, without going through the liquid state.
Iodine is a solid that sublimes. When a mixture of iodine and sand is heated in a beaker, the iodine changes from solid to
vapour directly.
These vapours of iodine can be obtained by cooling. They will change back to solid directly.
Answer: Option C. ->
Glucose in water
:
C
A mixture is a combination of two or more substances in which each substance retains its individual chemical properties.
A homogeneous mixture is a solid, liquid, or gaseous mixture that has the same proportions of its components throughout any given sample. Examples- glucose in water, acetone and water, alloys of metals, sugar and water, etc.
Conversely, a heterogeneous mixture has components whose proportions vary throughout the sample. Examples- sugar and oil, soap lather, sugar and salt.
:
C
A mixture is a combination of two or more substances in which each substance retains its individual chemical properties.
A homogeneous mixture is a solid, liquid, or gaseous mixture that has the same proportions of its components throughout any given sample. Examples- glucose in water, acetone and water, alloys of metals, sugar and water, etc.
Conversely, a heterogeneous mixture has components whose proportions vary throughout the sample. Examples- sugar and oil, soap lather, sugar and salt.
Answer: Option C. ->
magnetic separation
:
C
:
C
Magnetic separation is a method used if one of the components of the mixture is magnetic in nature .This method is used as one of the component gets attracted towards the magnet. In the given case, iron filings get attracted to a magnet while silver filings wont and hence, can be separated by magnetic separation.
Answer: Option B. ->
Mercury
:
B and C
Mercury is the only metal that is a liquid at room temperature. Its melting point is -38.83 °C.
Bromine is the only nonmetal that is a liquid at room temperature. Its melting point is -7.2 °C. Majority of the elements are solids.
:
B and C
Mercury is the only metal that is a liquid at room temperature. Its melting point is -38.83 °C.
Bromine is the only nonmetal that is a liquid at room temperature. Its melting point is -7.2 °C. Majority of the elements are solids.
Answer: Option C. ->
Sedimentation
:
C
Sedimentation is the tendency for the particles in a suspension to settle down. It is a physical water treatment process used to remove suspended solids from water naturally.
:
C
Sedimentation is the tendency for the particles in a suspension to settle down. It is a physical water treatment process used to remove suspended solids from water naturally.
Answer: Option C. ->
It is used to separate colours in a dye
:
A, B, C, and D
Chromatography is the technique used for the separation of those solutes that dissolve in the same solvent. The word chromatography was derived from a greek word 'kroma', which means colour.
In this technique, the rate of movement of the components is taken advantage of to separate them. The components are dissolved in a solvent and are made to move through an adsorbent solid. The component that is more soluble in the solvent, dissolves faster and gets separated faster in the medium.
The ink that we use has water as a solvent and a dye is dissolved in it. Through chromatography, it is possible to separate the dye from ink and also to separate drugs from blood.
:
A, B, C, and D
Chromatography is the technique used for the separation of those solutes that dissolve in the same solvent. The word chromatography was derived from a greek word 'kroma', which means colour.
In this technique, the rate of movement of the components is taken advantage of to separate them. The components are dissolved in a solvent and are made to move through an adsorbent solid. The component that is more soluble in the solvent, dissolves faster and gets separated faster in the medium.
The ink that we use has water as a solvent and a dye is dissolved in it. Through chromatography, it is possible to separate the dye from ink and also to separate drugs from blood.
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