Advertisements
Advertisements
प्रश्न
Explain the terms ‘chemical formula’.
उत्तर १
Chemical formula is a representation of a substance either element or compound by means of symbols.
उत्तर २
Chemical Formula: “A molecule of a substance element or compound could be represented by symbols. Representation known as chemical formula i.e. molecular formula of oxygen gas is O2 water H2O, hydrochloric acid HCl etc.
APPEARS IN
संबंधित प्रश्न
Write the names and symbols of the first twenty elements that you have studied in class VI & VII.
Write the symbols of helium, silver, krypton, antimony, barium.
Select elements and compounds from the following list: Iron, plaster of paris, chalk, common salt, copper, aluminium, calcium oxide, cane sugar, carbon, silica, sodium sulphate, uranium, potassium carbonate, silver, carbon dioxide.
Give two symbols which have been derived from the " Latin names" of the elements.
Explain the significance of the symbol H.
What is a symbol? What information does it convey?
Match the symbols of metallic elements – with their correct combining power or capacity.
(a) K
(b) Zn
(c) Al
(d) Na
(e) Ca
Combining power or capacity – A : 3 ; B : 2 ; C : 1. (positive valencies)
In the chemical word equation – Zinc + Sulphuric acid → Zinc sulphate + Hydrogen
The molecular equation is :
Zn + H2SO4 → ZnSO4 + H2[g].
State what [g] represents.
State which element exists in the highest percentage in human body.
Give the symbol of the following element:
Carbon
Give the symbol of the following element:
Xenon
State the type of element for the following:
Mercury
Give three reasons why – carbon dioxide is considered a compound, while carbon – an element.
Give the formula of the following acid:
Nitric
Give the formula of the following acid:
Sulphuric
State whether the following ion or radical given below of a non-metallic element exhibits valency: 1–, 2– or 3–. (write the ion or radical with the correct valency).
Bisulphate
What does the symbol '(s)' present in a chemical equation, mean?
The chemical symbol for sodium is
The first letter of a symbol is always written as a ______ letter and the second letter as a ______ letter.
