Tag: quantitative chemistry

Questions Related to quantitative chemistry

The molecular weights of $O _2$ and $N _2$ are $32$ and $28$ respectively. At $15^0$C, the pressure of $1$gm $O _2$ will be the same as that of $1$ gm $N _2$ in the same bottle at the temperature:

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $-21^0$C

  2. $-13^0$C

  3. $15^0$C

  4. $56.4^0$V

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Correct Option: B
Explanation:
Temperature of $O _{2}$ $=273+15=298 K$

Temperature of $N _{2}$ $=x$

As $n$ $\propto$ $\dfrac 1T$, as pressure is constant.

$\Longrightarrow { n } _{ 1 }{ T } _{ 1 }={ n } _{ 2 }{ T } _{ 2 }\Longrightarrow \left( \cfrac { 1 }{ 32 }  \right) \left( 298 \right) =\left( \cfrac { 1 }{ 28 }  \right) \left( x \right) \\ \Longrightarrow x=\cfrac { 28 }{ 32 } \times 298=260.75K$

Temperature in $^oC=260.75-273=-13 ^oC$

Hence, option $B$ is correct.

When 4 l of nitrogen completely reacts with hydrogen, what would be the volume of ammonia gas formed?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. 2 l

  2. 4 l

  3. 5 l

  4. 8 l

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Correct Option: D
Explanation:

Reaction:
$N _2+3H _2  \rightarrow 2NH _3$
 1     3               2
so 4 litre of nitrogen will produce 8 litre of $NH _3$

Gram molar volume for a gas is always considered at ___ conditions.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. NTP

  2. STP

  3. variable temperature

  4. none of these

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Correct Option: B
Explanation:

Since volume is a dependent variable and it depends on pressure and temperature always so temperature and pressure should be specified when volume of gas is considered. For this certain standard conditions are taken as 273 K and 1 atm pressure.
And at STP, molar volume is 22.4 litre.

Two gases A and B are taken in same volume containers under similar conditions of temperature and pressure. In container A, there are '2N' molecules of gas A. The number molecules does container B have :

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. N

  2. 0.5N

  3. 2N

  4. 4N

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Correct Option: C
Explanation:
1. According to Avogadro's law, the equal volume of gases under a similar condition of pressure and temperature contain equal no. of molecules. 
Therefore the number of molecules in container B will also be 2N.

2. As we know, one mole of each gas occupies 22.4-litre volume and one mole of gas contains NA molecules at STP.

So at the same temperature and pressure, the equal volume of gas contains equal no of molecules.

Therefore the number of molecules in container B will also be 2N.

Therefore, the option is C.

Which scientist discovered that the same amount of space was occupied by equal numbers of molecules of gases, irrespective of whether it was hydrogen or chlorine or fluorine?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. Gay-Lussac

  2. Avogadro

  3. Marconi

  4. Wohler

Show answer
Correct Option: B
Explanation:

Avogadro first discovered it.
It states that $1$ $mole$ of any element or compound have $6.022\times 10^{23}$ atoms or molecules present at any constant temperature and pressure.

When a certain quantity of oxygen was ozonised in suitable apparatus, the volume decreased by $4\ ml$. On addition of turpentine the volume further decreased by $8\ ml$. All volumes were measured at the same temperature and pressure. From these data, establish the formula of ozone.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $\displaystyle :O _{3}$

  2. $\displaystyle :O _{4}$

  3. $\displaystyle :O _{5}$

  4. $\displaystyle :O _{6.5}$

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Correct Option: A
Explanation:

Let the formula of ozone be $\displaystyle O _n $
When a certain quantity of oxygen was ozonised in suitable apparatus, the volume decreased by 4 ml.
$\displaystyle  nO _2 \rightleftharpoons 2O _n $
$\displaystyle n-2 \propto 4 $
On addition of turpentine the volume further decreased by 8ml. All volumes were measured at the same temperature and pressure.
$\displaystyle  8mL = 2\times 4mL $
$\displaystyle 2=2n-4 $
$\displaystyle 6=2n $
$\displaystyle  n=3$
Thus, the formula of ozone is $\displaystyle O _3 $.

Two gases A and B which react according to the equation $\displaystyle :aA _{(g)}+bB _{(g)}\rightarrow cC _{(g)}+dD _{(g)}$ to give two gases C and D are taken (amount not known) in an Eudiometer tube (operating at a constant pressure and temperature) to cause the above. If on causing the reaction there is no volume change observed then which of the following statement are correct :

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. $\displaystyle :\left ( a+b \right)= \left ( c+d \right )$

  2. Average molecular mass may increase or decrease if either of A or B is present in limited amount.

  3. Vapour Density of the mixture will remain same throughout the course of reaction.

  4. Total moles of all the component of mixture will change.

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Correct Option: A,C

Statement 1: At the same temperature and pressure, 1 L of hydrogen gas and  1 L of neon gas have the same mass.
Statement 2: Equal volumes of ideal gases at the same temperature and pressure contain the same number of moles.

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. Both statement 1 and statement 2 are correct and statement 2 is the correct explanation of statement 1

  2. Both statement 1 and statement 2 are correct but Statement 2 is not the correct explanation of Statement 1

  3. Statement 1 is correct but statement 2 is incorrect

  4. Statement 1 is incorrect but statement 2 is correct

  5. Both the statement 1 and statement 2 are incorrect

Show answer
Correct Option: D
Explanation:

Statement 1: At the same temperature and pressure, 1 L of hydrogen gas and  1 L of neon gas have the same volume.
Statement 2: Equal volumes of ideal gases at the same temperature and pressure contain the same number of moles.
For example, 1 mole of any gas at STP will occupy a volume of 22.4 L.
Hence, statement 1 is not correct but statement 2 is correct.

"All gases have the same number of moles in the same volume at constant temperature and pressure:. This statments belongs to :

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. Boyle's law

  2. Charles's law

  3. Avogadro's principle

  4. ideal gas law

  5. Dalton's law

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Correct Option: C
Explanation:

Avogadro's law (sometimes referred to as Avogadro's hypothesis or Avogadro's principle) is an experimental gas law relating volume of a gas to the amount of substance of gas present.
Avogadro's law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules".
For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant.

Avogadro's law shows the relationship between which two variables?

chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

  1. Volume and number of moles

  2. Pressure and number of moles

  3. Volume and pressure

  4. Temperature and pressure

  5. Temperature and number of moles

Show answer
Correct Option: A
Explanation:

(A) : Volume and number of moles, : at constant pressure.
Avogadro Law: At the same condition of temperature and pressure the volume of the gas is directly proportional to the number of the moles.