Some basic concepts of chemistry practice · Mixed difficulty

The hardness of water is usually expressed in:

7.5 gr of a gas occupy 5.8 L of volume at STP, the gas is

Mixing up of equal volumes of $0.1\;M\;\mathrm{NaOH}\;\mathrm{and}\;0.1\;M\;\mathrm{C}{\mathrm{H}_3}\mathrm{COOH}$ yields a solution which is:

$\mathrm{CH_4(g})+2 \mathrm{O_2(g}) \longrightarrow \mathrm{CO_2(g})+2 \mathrm{H}_2 \mathrm{O(g})$
According to the above chemical reaction, following information have been given.

(i) One mole of $\mathrm{CH}_4(\mathrm{g})$ reacts with two moles of $\mathrm{O}_2(\mathrm{g})$ to give one mole of $\mathrm{CO}_2(\mathrm{g})$ and two moles of $\mathrm{H}_2 \mathrm{O}(\mathrm{g})$

(ii) One molecule of $\mathrm{CH}_4(\mathrm{g})$ reacts with 2 molecules of $\mathrm{O}_2(\mathrm{g})$ to give one molecule of $\mathrm{CO}_2(\mathrm{g})$ and 2 molecules of $\mathrm{H}_2 \mathrm{O}(\mathrm{g})$

(iii) $22.7 \mathrm{~L}$ of $\mathrm{CH}_4(\mathrm{g})$ reacts with $45.4 \mathrm{~L}$ of $\mathrm{O}_2$ to give $22.7 \mathrm{~L}$ of $\mathrm{CO}_2(\mathrm{g})$ and $45.4 \mathrm{~L}$ of $\mathrm{H}_2 \mathrm{O}(\mathrm{g})$

(iv) $16 \mathrm{~g}$ of $\mathrm{CH}_4(\mathrm{g})$ reacts with $2 \times 32 \mathrm{~g}$ of $\mathrm{O}_2(\mathrm{g})$ to give $44 \mathrm{~g}$ of $\mathrm{CO}_2(\mathrm{g})$ and $2 \times 18 \mathrm{~g}$ of $\mathrm{H}_2 \mathrm{O}(\mathrm{g})$

From these information the correct interconversion should be

Which of the following contains greatest number of oxygen atoms?

The $\mathrm{O}^{18} / \mathrm{O}^{16}$ ratio in some meteorites is greater than that used to calculate the average atomic mass of oxygen on earth. The average mass of an atom of oxygen in these meteorites is _____ that of a terrestrial oxygen atom?

Assertion: Equivalence point is a theoretical value.
Reason: End point is an experimental value.

Mass of $C{O_2}$ produced by heating 40 g of 20% pure lime stone

Mole fraction of solvent in $10 \%\left(\frac{w}{w}\right)$ aqueous $\mathrm{NaOH}$ is

0.1 M solution of KI reacts with excess of $\mathrm{H}_2 \mathrm{SO}_4$ and $\mathrm{KIO}_3$ solution. According to equation

$5 \mathrm{I}^{-}+\mathrm{IO}_3^{-}+6 \mathrm{H}^{+} \rightarrow 3 \mathrm{I}_2+3 \mathrm{H}_2 \mathrm{O}$

Identify the correct statements:

(A) 200 mL of KI solution reacts with 0.004 mol of $\mathrm{KIO}_3$

(B) 200 mL of KI solution reacts with 0.006 mol of $\mathrm{H}_2 \mathrm{SO}_4$

(3) 0.5 L of KI solution produced 0.005 mol of $\mathrm{I}_2$

(4) Equivalent weight of $\mathrm{KIO}_3$ is equal to $\left(\frac{\text {Molecular weight}}{5}\right)$

Choose the correct answer from the options given below:

Chlorophyll contains $2.68 \%$ of magnesium by mass. Calculate the number of magnesium atoms in $3 \mathrm{~g}$ of chlorophyll.

Which has the maximum number of molecules among the following

In 4 moles of ethane, the number of molecules of ethane are

Assertion (A): Hydrogen burns with a pop sound and oxygen is a supporter of combustion but water is used as a fire extinguisher.
Reason (R): The properties of a compound are different from those of its constituent elements.

24 g of metal react with an acid and liberated 22.4 litres of hydrogen at STP. The equivalent wt of the metal is

Statement I: Equimolar solutions of $\mathrm{H}_3 \mathrm{PO}_3$ and $\mathrm{H}_2 \mathrm{SO}_4$ are not equinormal.

Statement II: Both are dibasic acid and Molarity $\times 2=$ normality.

How many millilitres of a $0.05 \mathrm{~M} \mathrm{~KMnO}_4$ solution are required to oxide $2.0 \mathrm{~g}$ of $\mathrm{FeSO}_4$ in a dilute acid solution? $(\mathrm{Fe}=56, \mathrm{S}=32, \mathrm{O}=16)$.

The density of $3 \mathrm{M}$ solution of $\mathrm{NaCl}$ is $1.25 \mathrm{~g} \mathrm{~mL}^{-1}$. Calculate the molality of the solution.

A sample of $\mathrm{Al}{\mathrm{F}_3}$ contains $3.0 \times {10^{24}}$ F ions. The number of formula units of this sample are

Assertion (A) : 4 moles of ${KClO}_3$ (50 % pure) gave 3 moles of $\mathrm{O}_2$ on heating strongly and thus yield is $100 \%$

$2{KClO}_3 \longrightarrow 2 {KCl}+3 {O}_2$

Reason (R) : 3 moles of ${O}_2$ are obtained from 2 moles of ${KClO}_3$.

The number of significant figures in 60.0001 is

4 g-atom of Ag contains:

5 moles of $A{B_2}$ weight $125 \times {10^{ - 3}}kg$ and 10 moles of ${A_2}{B_2}$ weight $300 \times {10^{ - 3}}kg$. The molar mass of $A\left( {{M_A}} \right)$ and molar mass of $B\left( {{M_B}} \right)$ in kg $\mathrm{mo}{\mathrm{l}^{ - 1}}$ are

Assertion: Sulphate is estimated as $\mathrm{BaSO}_4$ and not as $\mathrm{MgSO}_4$.
Reason: Ionic radius of $\mathrm{Mg}^{2+}$ is smaller than $\mathrm{Ba}^{2+}$.

Mole fraction of A in water is 0.2. The molality of A in water is:

A quantity of $50 \mathrm{~g}$ of water is saturated with ${HCl}$ gas to get $75 \mathrm{~ml}$ of solution containing $40 \% \, {HCl}$ by mass. The density of solution formed is

An ethanolic solution of naphthalene contains 0.25 mole fraction of solute. Molality of solution is

Element $\mathrm{X}$ reacts with oxygen to produce a pure sample of $\mathrm{X}_2 \mathrm{O}_3.$ In an experiment it is found that $1 \mathrm{~g}$ of $\mathrm{X}$ produces $1.16 \mathrm{~g}$ of $\mathrm{X}_2 \mathrm{O}_3.$ Calculate the atomic weight of $\mathrm{X}.$ (Given atomic weight of oxygen, $16.0 \mathrm{~g} \mathrm{~mol}^{-1}$)

Potassium combines with two isotopes of chlorine $\left({ }^{35} {Cl} \text{ and } { }^{37} {Cl}\right)$ respectively to form two samples of ${KCl}.$ Their formation follows the law of

A molal solution is one that contains one mole of a solute in: