Advertisements
Advertisements
प्रश्न
Which of the following is not an element ?
विकल्प
graphite
germanium
silica
silicon
Advertisements
उत्तर
Silica.
Silica is a compound made up of Si (silicon) and O (oxygen) and chemically called Silicon dioxide.
APPEARS IN
संबंधित प्रश्न
Select the correct alternative
The molecules can move freely anywhere in
- gases
- liquids
- solids
- none of the above
Name the processes involved in two cases.
Fill in the blank
All matter is made up of tiny particles called ______
What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain during Brownian motion.
What is meant by saying that metals are lustrous ?
Which of the following substances are elements ?
Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine
State any two properties for believing that aluminium is a metal.
Name a metal which forms amalgams.
The property/properties which enable copper metal to be used for making electric wires is/are :
There are three substances X, Y and Z. The substance X does not have a fixed melting point or boiling point and it still shows the individual properties of its constituents. The substance Y is a pure substance which occurs in nature as such. The substance Y has a fixed melting point and boiling point but it cannot be broken down into simpler substances by any chemical means. The substance Z is also a pure substance whose properties are entirely different from those of its constituents. The substance Z can, however, be divided by electrolysis into two substances which belong to the same class of substances as Y.
- What type of substance could X be ? Name one substance like X.
- What type of substance could Y be ? Name one substance like Y.
- What type of substance could Z be ? Name one substance like Z.
- Which process involves absorption or release of an appreciable amount of energy : formation of substance X or formation of substance Z ?
- Name the three groups into which all the substances like Y are divided on the basis of their properties.
There is a large group of materials P which can be divided into three groups Q, R and S on the basis of their properties. The substances belonging to group Q can be solids, liquids or gases. The solids belonging to group Q are usually electrical insulators. Most of the substances of group R are solids which are good conductors of electricity. The substances belonging to group S are neither insulators like Q nor good conductors like R. The properties of S are intermediate between those of Q and R.
- What could the group of materials P be ?
- Name the substances Q. Give two examples of such substances.
- Name the substances R. Write two examples of such substances.
- Name the substances S. Give two examples of such substances.
- Out of Q, R and S, which substances are malleable and ductile ?
Out of a colloid, solution and a suspension :
which one has the largest particles ?
Which of the following will show Tyndall effect ? Why ?
- Salt solution
- Starch solution
- Milk
- Copper sulphate solution
Which of the following represents the solubility of sugar in water at 20°C ?
Name the process by which all the dye can be recovered from black ink.
Fill in the following blanks with suitable words :
If a mixture contains iron filings as one of the constituents, it can be separated by using a .......................
Describe a method for separating a mixture of iron filings and sulphur powder other than that by using a magnet.
Define the term matter.
Define the term matter.
