Answer:
<span>The mole concept is important in chemistry because, "</span>Atoms and molecules are very small and the mole concept allows us to count atoms and molecules by weighing macroscopic amounts of material".
Explanation:
To understand this question lets take an example of Hydrogen atom. Let suppose you need to react Hydrogen with Oxygen. You need exactly Two Hydrogen atoms and one Oxygen atom to form one water molecule.
The mass of 1 hydrogen atom is 1.76 × 10⁻²⁴ grams. How will you count the Hydrogen atoms??? How can you measure exactly for 1 Million Hydrogen Atoms???
Answer to these questions and Calculations lies in Mole. It is found that 1 Mole of Hydrogen weights exactly 1.008 gram and contains 6.022 × 10²³ atoms. Now, having this reference in hand you can calculate for any number of Hydrogen atoms.
Result:
So the Mole helps us to zoom a microscopic level to a macroscopic level. :)
The proportion of carbon and oxygen is different in samples of the gas
Answer:
C
Explanation:
The ions are first accelerated electrically, and then bended magnetically to sort them and record them.
Answer: 
Explanation:
First we have to calculate the heat absorbed by bomb calorimeter
Formula used :
= heat absorbed by calorimeter = ?
= specific heat of = 10.69 kJ/K
= final temperature = 
= initial temperature = 
As heat absorbed by calorimeter is equal to the heat released by acetylene during combustion.
Thus 1.53 gram of acetylene releases heat of combustion = 258.7kJ
So, 26.04 g/mole of acetylene releases heat of combustion 
Therefore, the heat of combustion of acetylene is,
