Atom is the
most basic unit of matter. They are the general term used to describe pieces of
matter. But a different kind of atom makes up an element. A combination of atom of different elements
creates a molecule. For example, you have water; it has a chemical formula of
H2O. If you separate H from O, you have two atoms. Two atoms for hydrogen and
one atom for oxygen. However, they are of different elements. And when you
combine them to form H2O, you create a molecule.
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Answer:
A group is a column of elements in the periodic table of the chemical elements.
So, the columns on the periodic table are called groups.
Answer:
The correct answer is
B.

Explanation:
Enthalpy of reaction :
It is the amount of energy released/absorbed when one mole of the substance is formed from the reactant at a constant pressure.
The enthalpy of a reaction can be calculated using :









Please note that :
The carbon monoxide , CO should be taken as C triple bond O. Not C=O .
So , the bond energy =1072 is used

What are the names of the two magnetic poles?
Ur answer is
North and South
Answer:
The osmotic pressure of cell is
KPa
Explanation:
As we know the osmotic pressure is equal to

Where
i is the Van Hoff factor
c is the concentration of solution
R is the ideal gas constant
and T is the temperature.
Substituting the given values, we get -

KPa