Single Choice

Which of the following formulae is not correctly depicted?

AMolar mass = $$\cfrac{Mass \ of \ substance }{Moles \ of \ substance}$$
BNumber of moles of a substance = $$\cfrac{Mass \ of \ substance }{ Molar \ mass }$$
CNumber of molecules = $$\cfrac{Mass \ of \ the \ substance}{Molar \ mass} \times Avogadro's \ no.$$
D$$Mole \times Molar \ mass=$$ Number of molecules
Correct Answer

Solution

Molar mass = mass per mole of the substance = $$\dfrac {Mass\ of\ substance}{Moles\ of\ substance}$$

Rewriting it as: Number of moles of a substance = $$\dfrac{Mass\ of\ substance}{Molar\ mass}$$

Also, number of moles of a substance $$\times$$ Molar mass = mass of the substance.

Number of molecules = Number of moles $$\times$$ Avogadro's constant = $$\dfrac{Mass\ of\ substance}{Molar\ mass} \times Avogadro′s\ no$$.

SIMILAR QUESTIONS

Mole Concept

$$10$$ grams each of $$O_{2},\ N_{2}$$ and $$Cl_{2}$$ are kept in three bottles. The correct order of arrangement of bottles containing decreasing number of molecules is:

Mole Concept

The density of water is $$1.00$$ g/ml at $$4^0 C$$. Number of water molecules (as multiples of $$N_o$$) present in $$18$$ ml water at this temperature is __________.

Mole Concept

Arrange the following in increasing order of number of molecules I. 0.5 mol of $${H}_{2}$$ II. 4.0 g of $${H}_{2}$$ III. 18 g of $${H}_{2}O$$ IV. 2.2 g of $$C{O}_{2}$$

Mole Concept

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is $$ 1:4$$. The ratio of number of their molecules is :

Mole Concept

Which has the maximum number of molecules among the following?

Mole Concept

The number of water molecules is maximum in :

Mole Concept

Which has the maximum number of molecules among the following?

Mole Concept

The number of molecules of $$H_2O$$ in $$90$$ g of water is?

Mole Concept

If $$3$$ moles of ethane $$\displaystyle \left( { C }_{ 2 }{ H }_{ 6 } \right) $$ are given, calculate the following: (i) Number of moles of carbon atoms. (ii) Number of moles of hydrogen atoms. (iii) Number of molecules of ethane.

Mole Concept

HCl is produced in the stomach which can be neutralised by $$Mg(OH)_2$$ in the form of milk of magnesia. How much $$Mg(OH)_2$$ is required to neutralise one mole of stomach acid?

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