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Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

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?

  1. Gay-Lussac

  2. Avogadro

  3. Marconi

  4. Wohler
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

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.

  1. $\displaystyle \:O _{3}$
  2. $\displaystyle \:O _{4}$
  3. $\displaystyle \:O _{5}$
  4. $\displaystyle \:O _{6.5}$
Reveal answer Fill a bubble to check yourself
A Correct answer
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 $.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

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 :

  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.
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

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.

  1. <p>Both statement 1 and statement 2 are correct and statement 2 is the correct explanation of statement 1</p>

  2. <p>Both statement 1 and statement 2 are correct but Statement 2 is not the correct explanation of Statement 1</p>

  3. <p>Statement 1 is correct but statement 2 is incorrect</p>

  4. <p>Statement 1 is incorrect but statement 2 is correct</p>

  5. <p>Both the statement 1 and statement 2 are incorrect</p>
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

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

  1. Boyle's law

  2. Charles's law

  3. Avogadro's principle

  4. ideal gas law

  5. Dalton's law
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

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

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice chemistry quantitative chemistry avogadro hypothesis avogadro's law avogadro law

Statement I : At STP, 22.4 liters of He will have the same volume as one mole of $\displaystyle { H } _{ 2 }$ (assume ideal gases).
Statement II : One mole or 22.4 liters of any gas at STP will have the same mass.

  1. true, false

  2. false, true

  3. true, true, correct explanation

  4. true, true, not correct explanation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Avogadro’s law states that under the same conditions of temperature and pressure, equal volumes of different gases contain an equal number of molecules. This empirical relation can be derived from the kinetic theory of gases under the assumption of a perfect (ideal) gas. The law is approximately valid for real gases at sufficiently low pressures and high temperatures.
At STP, all gas have same volume for 1 mol of gas and that volume is always equal to the 22.4 L.  

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Which of the following is an insulator?

  1. Wood

  2. Iron

  3. Graphite

  4. Silver
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Insulators donot conduct electricity due to the absence of ions or electrons.

Iron is metal therefore has pool of electrons on the surface and is a conductor.
Graphite has extensive $\pi$ electron cloud and is thus a conductor.
Silver is a metal and is a very good conductor of electricity.
Wood is made of organic molecule, thus its an insulator.
Option A is correct

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Insulators:

  1. conduct electricity.

  2. do not conduct electricity.

  3. conduct electricity only at low temperatures.

  4. conduct electricity at room temperature.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Insulators are materials that prevent the flow of electric current because they have very few free electrons or ions to carry charge. Conductors, by contrast, allow electricity to pass through them easily.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

What is [CN-] in a solution prepared by mixing 100ml 0.1M $KCN$ and 100ml 0.1M $HCl$. (Ka of $HCN$ is 510^-6 M)?

  1. $5\times10^{-4} M$
  2. $2\times10^{-6} M$
  3. $2\times10^{-5} M$
  4. $4 \times10^{-6} M$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mixing 100 ml of 0.1M KCN and 100 ml of 0.1M HCl results in a total volume of 200 ml containing 0.01 moles of HCN and neutralized chloride ions. The concentration of HCN is 0.01 mol / 0.2 L = 0.05 M. Since HCN is a weak acid, [H+] = sqrt(Ka * C) = sqrt(5 * 10^-6 * 0.05) = sqrt(2.5 * 10^-7) = 5 * 10^-4 M.