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Accounting for share capital

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Class 10 Class 12

From where the word stoichometry has been derived?

The word ‘stoichiometry’ is derived from two Greek words - stoicheion (meaning element) and metron (meaning measure).

What is the S.I. unit of molarity?

The SI unit of molarity si mol L-1

What do you understand by limiting reactant?


When in reaction, one rectant is in excess over the other. The reactant which is present in the lesser amount gets consumed after  sometimes and after no further reaction takes place whatever be the amount of the other reactant present. Hence, the reactant which gets consumed, limits the amount of product formed and, therefore, called the liminting reagent.

Define molality (m).

Molality of a solution is defined as the number of moles of solute dissolved per kg of solvent.

Molality left parenthesis straight m right parenthesis space equals space fraction numerator No. space of space moles space of space solute over denominator Mass space of space solvent space left parenthesis in space grams right parenthesis end fraction cross times space 1000

What do you understand by ‘rounding off’?

The rules for rounding off the non significant figures in the measurements are as under:

1. If the digit following the last digit to be retained is less than 5, the last digit is left unchanged. For example,
4·22 is rounded off to 4·2
4·14 is rounded off to 4·1
4·34 is rounded off to 4·3

2. If the last digit happens to be five (as in 4·335), then a digit before five is checked whether it is odd or even.
If it is odd, then it is increased by one. e.g.
4·335 is rounded off to 4·34
15·275 is rounded off to 15·28
If the digit before five is even, then it is retained as such. e.g.,
14·145 is rounded off to 14·14
6·225 is rounded off to 6·22
0·085 is rounded off to 0·08

3. If the last digit is greater than 5, the last-digit to be retained is increased by one. e.g.,
2·26 is rounded off to 2·3
4·68 is rounded off to 4·7
16·59 is rounded off to 16·6