Matter and Its Composition Test - 6

Scientific theories are constructed in order to explain, predict, and understand phenomena. This could include explanations for the movement of planets, weather patterns, or the behavior of animals.

Therefore, option (d) is correct.

In solids, the particles are arranged in a regular pattern. They are held together by strong forces. This is why solids have a fixed shape. You cannot squash or change the volume of solids.

Therefore, option (d) is correct.

In a solid, the strong attractions between the particles hold them tightly packed together. Even though they are vibrating this is not enough to disrupt the structure. When a solid is heated the particles gain energy and start to vibrate faster and faster.

Therefore, option (d) is correct.

Iron is a chemical element with symbol Fe and atomic number 26. Classified as a transition metal, Iron is a solid at room temperature.

Therefore, option (c) is correct.

The solid begins to go from a solid-state to a liquid state — a process called melting. The temperature at which melting occurs is the melting point (mp) of the substance.

Therefore, option (d) is correct.

In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and plasma. Matter in the liquid state maintains a fixed volume but has a variable shape that adapts to fit its container.

Therefore, option (d) is correct.

Solids have the highest force of attraction followed by liquid and then the gas has the least attractive forces. Therefore the particles of solid are closely packed and the particles of gas are free to move.

If you increase the mass without increasing the volume, the density increases. Increase volume without increasing mass decreases the density. So density is directly proportional to mass and inverse proportion to volume.

Therefore, option (c) is correct.

The properties of a solid are:

1) A solid has a definite shape and volume. 

2) Solids in general have higher density. 

3) In solids, intermolecular forces are strong. 

4) The diffusion of a solid into another solid is extremely slow.

Therefore, option (a) is correct.

But in 1905, physicist Albert Einstein explained that the pollen grains were being moved by individual water molecules. This confirmed that atoms and molecules did exist, and provided evidence for particle theory.

Therefore, option (d) is correct.

Gases and liquids are made of molecules or inert atoms that are moving about relative to each other. In a liquid, the molecules are constantly in contact with others; in a gas, they are widely spaced except when they happen to collide.

Therefore, option (c) is correct.

An irregular motion of small particles suspended in a liquid or a gas, caused by the bombardment of the particles by molecules of the medium: first observed by Robert Brown in 1827.

Therefore, option (b) is correct.

In the event of inhalation of chlorine gas, immediate medical attention must be sought. Bromine is a toxic and irritating liquid with high vapor pressure. Elemental bromine is widely used. Bromine may only be used in a well-ventilated fume cupboard.

Therefore, option (a) is correct.

The process by which a substance moves from the liquid state to the gaseous state is called boiling. The temperature at which a liquid begins to boil is called the boiling point (bp). The bp is dependent on atmospheric pressure, but for water at sea level, it's 212°F or 100°C.

Therefore, option (b) is correct.

Democritus proposed 5 points to his theory of atoms. These are:

1. All matter is composed of atoms, which are bits of matter too small to be seen. These atoms CANNOT be further split into smaller portions.

2. There is a void, which is empty space between atoms.

3. Atoms are completely solid.

4. Atoms are homogeneous, with no internal structure.

5. Atoms are different in their sizes, their shapes, and their weights.

Therefore, option (a) is correct.