Test: Is Matter Around Us Pure - 2 - UPSC

The most abundant element in earth’s crust is Oxygen. It is present in earth crust in form of oxide, carbonate etc. of metal.

The density of ice at its melting point is less than density of water. Ice have less density than water, that is why ice float on water.

A nanometer (nm) is a decimal fraction of the base SI unit of length, the meter, which is defined as the length of the path travelled by light in vacuum during a time interval of 1/299,792,458 of a second.

22 carat gold is a homogeneous mixture in which gold is mixed with small amount of copper or silver.

A substance that can be beaten into thin sheets and drawn into thin wire is both malleable and ductile. Gold is most malleable and ductile element.

Mixtures are one product of mechanically blending or mixing chemical substances such as elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup.
A chemical compound is a substance composed of two or more different elements chemically bonded together in a fixed proportion by mass. However, not all molecules are compounds. Compounds are pure substances that contain two or more elements combined in a definite fixed proportion.
Any substance that contains only one kind of an atom is known as an element. Because atoms cannot be created or destroyed in a chemical reaction, elements such as phosphorus (P4) or sulfur (S8) cannot be broken down into simpler substances by these reactions.
When a molecule is formed from elements of a different species it is a heteroatomic molecule. As an atom is the smallest particle of an element that retains the properties of that element, a molecule is the smallest particle of a compound.

Suspension: When the particle size is greater than 1000 nm, then the solution is considered as a suspension.

Distillation is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation. Simple distillation is used when the boiling points of chemicals in a mixture having large differences (more than 25°C). Fractional distillation is used when the boiling points of chemicals in a mixture are close to each-other, usually within 77°F (25°C). Fractionating columns used to separate the mixtures.

The chemical composition of the Universe is dominated by the hydrogen and helium produced in the Big Bang. The remaining 90 or so chemical elements are produced in stars and constitute only a few percent of the overall mass. Astronomers refer to these elements (all except hydrogen and helium) as metals, even though this includes elements such as carbon and oxygen which are not considered metals in the normal sense.
Chemical composition of the Sun

The correct answer is c as all the statements are false about the solubility. 

An emulsion s a colloidal solution formed by mixing of two immiscible liquids.

The coloured material from flower petals can be separated by chromatography process. Chromatography is used to separate materials present in solution in vary trace amount

The element that possesses characteristic of both metal and non-metal are called metalloid. Arsenic is the element that has properties of both metal and non-metal

Clouds and fogs are example of liquid in gas solution. Cloud is formed by combination of water vapour with dust particles. Fogs contain water vapour and gases.

Scattering of beam of light when passes through a solution is called tyndall effect. Colloidal solution shows the tyndall effect and scatter the beam of light.

NH₄Cl is separated from NaCl by heating the solid mixture in a test tube. NH₄Cl being sublime change into vapour which can be collected by cooling it. Nacl remain in test tube.

Hydrogen sulfide gas produces an offensive "rotten egg" or "sulfur water" odor and taste in the water. In some cases, the odor may be noticeable only when the water is initially turned on or when hot water is run. Heat forces the gas into the air which may cause the odor to be especially offensive in a shower. Occasionally, a hot water heater is a source of hydrogen sulfide odor. The magnesium corrosion control rod present in many hot water heaters can chemically reduce naturally occurring sulfates to hydrogen sulfide.

Brass is a homogenous mixture of 70% of Copper and 30% Zinc by mass. Copper and Zinc forms homogenous mixture as constituent particles are not visible

The liquid which contains some suspended particles are called suspension. The size of particle is more than 100nm.

Boiling point of water decreases with increase in altitude. At the top of mountain where the atmospheric pressure is less than 1 atm water boils below 100⁰C.

Thermometer - Instrument for measuring temperature

A thermometer is an instrument used to measure the temperature of a substance. It works on the principle of thermal expansion, where the temperature change causes the liquid or gas inside the thermometer to expand or contract, resulting in a corresponding change in the reading.

Key Points:
- The purpose of a thermometer is to measure the temperature of a substance accurately.
- It is commonly used in various fields such as weather forecasting, medical applications, cooking, and scientific research.
- The most common type of thermometer is the mercury-in-glass thermometer, where the mercury expands or contracts based on the temperature.
- Other types of thermometers include digital thermometers, infrared thermometers, and thermocouples.
- Thermometers can measure temperatures in different scales such as Celsius, Fahrenheit, and Kelvin.
- The accuracy of a thermometer depends on its calibration and proper usage.
- Thermometers are designed to be sensitive to temperature changes and provide precise measurements.
- They are generally made of glass or metal and can be found in various shapes and sizes.
- Thermometers are widely used in industries, laboratories, and households for monitoring and controlling temperature.
- The information provided by a thermometer helps in making informed decisions and maintaining optimal conditions for various applications.
In conclusion, a thermometer is an essential instrument for measuring the temperature of a substance accurately. It plays a crucial role in various fields and helps in monitoring and controlling temperature for different purposes.

The mixture in which particles are not distributed evenly and forms separate layer if left undisturbed. The mixture of Albumin and water forms a heterogeneous mixture

The size of particles in colloidal solution ranges from 10⁻⁵cm to 10⁻⁷cm. less than 10⁻⁵ is true solution and more than 10⁻⁷ is suspension.

(a) The process of centrifugation is used in dairies to separate cream from milk. Centrifugation is a method for separating the suspended particles of a substance from a liquid in which the mixture is rotated at a high speed in a centrifuge machine.
(b) Oil being lighter forms the top layer, while water being heavier forms the bottom layer. Oil can be separated by decantation. However, a more useful method for separating oil and water is with the separating funnel.
(c) Chromatography is a technique used to separate the chemical compounds (pigments) of a mixture. One of the most common types is called paper chromatography.
(d) Air can be separated into its components of air through fractional distillation. In the fractional distillation process, the liquid air is distributed through the fractional distillation column. Here, the liquid air is permissible to warm-up. The liquid oxygen will be gathered in the fractionating column.

Brass is a solid solution consisting of zinc and other metals (solutes) dissolved in copper (solvent).