Advertisements
Advertisements
प्रश्न
Which of the following substances are elements ?
Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine
उत्तर
Mercury, iron, diamond, nitrogen, graphite, hydrogen, oxygen, and chlorine are elements because these cannot be split further into two or more simpler substances.
APPEARS IN
संबंधित प्रश्न
The inter-molecular space is maximum in
Select the correct alternative
The molecules can move freely anywhere in
- gases
- liquids
- solids
- none of the above
Fill in the blank :
The substances which can flow are called ________
Name the property which enables metals to be drawn into wires.
State two physical properties on the basis of which metals can be distinguished from non-metals.
Give reason why copper metal is used for making electric wires.
Which of the following does not have a fixed melting point/boiling point ?
A solution contains 5.6 mL of alcohol mixed with 75 mL of water. Calculate the concentration of this solution.
What is a colloid ? Give two examples of colloids (or colloidal solutions)
Fill in the following blanks with suitable words :
Immiscible liquids are separated by using a .....................
What is fractional distillation ? What is the use of fractionating column in fractional distillation ?
Explain how, nitrogen , oxygen and argon gases are separated from air.
Naphthalene can be separated from sand :
The liquid air has three components X, Y and Z whose boiling points are : –186°C, –183°C and –196°C,
respectively. When liquid air is fed into a tall fractional distillation column from near its bottom and warmed
up slowly :
(a) Which component will be collected from near the bottom of the fraction distillation column ? Why ?
(b) Which component will be collected from the top part of the fractional distillation column ? Why ?
(c) Which component will be collected from the middle part of the fractional distillation column ? Why ?
(d) What could the component X, Y and Z be ?
The non S I and S I units of some physical quantities are given in column A and column B respectively. Match the units belonging to the same physical quantity:
| (A) | (B) | ||
| (a) | degree celsius | (i) | kilogram |
| (b) | centimetre | (ii) | pascal |
| (c) | gram per centimetre cube | (iii) | metre |
| (d) | bar | (iv) | kelvin |
| (e) | milligram | (v) | kilogram per metre cube |
In Aerosol the dispersed phase is liquid and the dispersion medium is gas.
The phenomenon of Evaporation takes place at the ______ of a liquid.
Evaporation is always accompanied by ______ in temperature.
Define the term matter.
