I.The element present in a compound can be separated by easy physical processes.
II. A solution is a mixture.
III. Mixture vary widely in their composition.
Which of the above statement are correct
D. II and III
The correct answer is II and III.
Statement II is correct because a solution is a type of mixture where two or more substances are evenly distributed.
Statement III is correct because mixtures can have varying compositions, meaning they can contain different amounts of substances mixed together.
Statement I is incorrect because elements in a compound cannot be separated by easy physical processes. Compounds are formed when two or more elements chemically combine, and they can only be separated by chemical processes.
I. Physical changes are easily reveresible.
II. Physical change do not produce new substance
III. Physical change do not involve change in mass.
Which of the above statement are correct?
E. I, II and III
Physical changes are easily reversible because they do not involve a change in the chemical composition or structure of a substance. Therefore, the original substance can be restored by reversing the physical change. Physical changes also do not produce new substances, as the arrangement or state of the particles may change, but the chemical identity remains the same. Additionally, physical changes do not involve a change in mass, as the total mass of the substances before and after the change remains constant. Therefore, all three statements are correct.
I. Chemical changes are not easily reversible.
II. Chemical changes produce new substances.
III. Chemical changes do not involve large energy changes.
Which of the above statement are correct
B. I and II
The correct answer is I and II. Chemical changes are not easily reversible because they involve the formation of new substances with different properties. This is supported by statement II, which states that chemical changes produce new substances. However, statement III is incorrect as chemical changes often involve large energy changes, such as in exothermic or endothermic reactions.
Which of the following is not a phsical change?
C. Burning of wax in a candle.
Burning of wax in a candle is not a physical change because it involves a chemical reaction. During burning, the wax undergoes combustion, which is a chemical process that results in the formation of new substances, such as carbon dioxide and water vapor. Physical changes, on the other hand, do not involve the formation of new substances and only alter the physical properties of a substance, such as its shape, size, or state of matter.
Which of the following is not a chemical change?
Photosynthesis is not a chemical change because it is a process where plants convert sunlight, water, and carbon dioxide into glucose and oxygen using the energy from sunlight. It involves a series of complex biochemical reactions, but the substances involved (sunlight, water, carbon dioxide, glucose, and oxygen) remain the same throughout the process. No new substances are formed, and there is no rearrangement of atoms or molecules. Therefore, photosynthesis is a biological process rather than a chemical change.
Which of the following processes would you use to obtain the components of a solution of copper sulphate in water
Evaporation would be the most suitable process to obtain the components of a solution of copper sulphate in water. This process involves heating the solution, causing the water to evaporate and leaving behind the copper sulphate crystals. Separating funnel is used to separate immiscible liquids, distillation is used to separate liquids with different boiling points, chromatography is used to separate components based on their affinity for a stationary phase, and sublimation is used to separate a solid from a gas without going through the liquid phase.
Which of the following mixture may be separated by using sublimation ?
I. Iodine and sand
II. Sand and sulphur
III. Sand and ammonium chloride.
E. I and III
Iodine and ammonium chloride can be separated by sublimation because both substances have the property of sublimation, which means they can change from a solid directly into a gas without going through the liquid phase. Sand, on the other hand, cannot be separated by sublimation as it does not have this property. Therefore, the correct answer is I and III.
Which of the following mixtures may be separated using a separating funnel ?
I. Water and Mercury
II. Water and common salt
III. Water and sulphuric acid
Water and mercury can be separated using a separating funnel because they are immiscible liquids, meaning they do not mix together. Water is denser than mercury, so when the mixture is poured into a separating funnel, the mercury will settle at the bottom and can be drained out separately from the water.
Which of the folloewing is not likely to be and element ?
I. When heated gives off a gas and leaves a solid residue.
II. Burns in air to form carbon dioxide and water.
III.Changes into a liquid and gives off a gas.
E. I,II and III
Which of the following process involves fractional distillation?
I. Separation of the component of liquid air
II. Separation of petroleum.
III. Separation of water and alcohol
D. I and II
Fractional distillation is a process used to separate mixtures of liquids with different boiling points. In the given options, both the separation of components of liquid air and the separation of petroleum involve fractional distillation. In the separation of liquid air, the different components such as nitrogen, oxygen, and argon are separated based on their boiling points. Similarly, in the separation of petroleum, the different fractions such as gasoline, diesel, and kerosene are obtained through fractional distillation.