Chemistry Mock Test- 5 - Class 9 MCQ

Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Transpiration is essentially evaporation of water from plant leaves.

Atoms are not able to exist independently.

• Atoms can accept or donate electrons to form a stable electronic configuration.
• It results in the formation of the molecule.
• Only inert gases, on the other hand, already have octet-filled configurations, allowing them to exist as atoms.

Rise in temperature gives the particles some energy to move faster.

option ( c) The mixture has properties similar to its compound is the correct answer. 

Explanation:- 

This is because in a mixture, the constituent particles are not mixed chemically.
They are mixed physically and can be separated fairly easily by physical Methods.
Thus they show the properties of components.
Example can be alloys.

Tap water is not a pure substance because it is mixed with chemicals that purify it and if it was from the ground it has naturally occurring minerals mixed in it.

LPG (liquefied petroleum gas) is a fuel that is made up of petroleum gas. On compressing this petroleum gas it forms liquid.

The process of converting a substance from the liquid state to the gaseous state at any temperature below its boiling point is called evaporation.

Helium only has 2 electrons and therefore it has a configuration of 1s². Because the 1s orbital is full with 2 electrons and any additional electrons would go in a new energy level. The electron configuration for Helium shows a full outer shell and is Helium is therefore called a Nobel Gas. This means it will not react with other atoms.

As we know , the  element having atomic no. 7 is nitrogen. The first shell is filled with 2 electrons. Remaining are 5 electrons, to fill second shell it need 3 more electrons and will become stable. Therefore, the valency of nitrogen is 3.

A combination of common salt and Iron filings is a mixture as there is no chemical reaction between them to form new substance.

The higher the temperature of liquid, the faster the rate of evaporation. This is due to the fact that as the liquid's temperature increase, the molecule of the liquid move about faster, thus increasing the rate of evaporation.

A fluid is a substance that continually deforms under an applied shear stress. Fluids are a subset of the phases of matter and include liquids, gases, plasmas, and to some extent, plastic solids.

Naphthalene because it changes from solid to gaseous without undergoing liquid as it is a sublime substance.

With increase in temperature, inter-particles forces decreases. As the melting point of solid A is less than Solid B. Solid B has more inter-particle forces of attraction. Higher the melting point more the inter-particle force.

As we know, in the periodic table; 
The symbol S  is used for sulphur 
The symbol Ag is used for silver
The symbol Na is used for sodium
The symbol K  is used for potassium
So, option ( d) is the correct✔ answer.

This statement is related with Aufbau principle.
According to Aufbau principle (also known as (n+l) rule), electrons are filled in different orbitals from lower (n+l) value orbital to higher (n+l) value orbital.
In case (n+l) value is same, electron is filled first in orbital with lower value of n.

Air is mixture and no energy change occurs during mixing of air. Cesium and gallium are liquid at room temperature. Pure substance have fixed melting and boiling points. Mixture is not a single substance.

Brownian movement arises because of the impact of the molecules of the dispersion medium with the colloidal particles. Since the impacts of the molecules of the dispersion medium on the colloidal particles are unequal (i.e. unbalanced bombardment), the result is zig-zag motion.

Mass of common salt (solute) = 40g
Mass of water (soluted) = 320g
Mass of solution = 320 + 40 = 360g
Concentration of solution = M(mass of solute) / mass of solution = 40/360 x 100 = 11.11%

  The correct answer is a

   Full-fat milk is standardised to 3.5% of fat and semi skimmed milk contains approximately 1.5% fat. Skimmed milk and buttermilk are very low in fat and, on average, contain 0.1 or 0.2% fat respectively.

The color of plasma is determined by the photons, which are emitted when the electrons recombine with the ions (or when excited electrons relax into a lower energy state).

Changes of state are physical changes in matter. They are reversible changes that do not involve changes in matter’s chemical makeup or chemical properties. Common changes of state include melting, freezing, sublimation, deposition, condensation, and vaporization.