Some Basic Concepts of Chemistry

The amount of carbon dioxide evolved upon complete combustion of $116 g$ of $n$-butane is
(Given: atomic mass in amu $\mathrm{H}=1, \mathrm{C}=12$ and $\mathrm{O}=16$ )

The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are

The number of hydrogen atoms present in 5.4 g of urea is:
(Given: Molar mass of urea : $60 \mathrm{~g} \mathrm{~mol}^{-1}$
$\mathrm{N}_{\mathrm{A}}: 6.022 \times 10^{23}$ particles $\mathrm{mol}^{-1}$ )

When $1 \mathrm{dm}^3$ of CO2 gas is passed over hot coke the volume of gaseous mixture after complete reaction at STP becomes $1.4 \mathrm{dm}^3$. The composition of the gaseous mixture at STP is :

Dalton's Atomic theory could not explain which of the following?

Among the following, choose the ones with equal number of atoms.
A. 212 g of $\mathrm{Na}_2 \mathrm{CO}_3(\mathrm{~s})$ [molar mass $=106 \mathrm{~g}$ ]
B. 248 g of $\mathrm{Na}_2 \mathrm{O}(\mathrm{s})$ [molar mass $=62 \mathrm{~g}$ ]
C. 2...

On complete combustion, 0.3 g of an organic compound gave 0.2 g of CO\(_2\) and 0.1 g of H\(_2\)O. The percentage
composition of carbon and hydrogen in the compound, respectively is:

\(1.0 \mathrm{~g}\) of \(\mathrm{H}_2\) has same number of molecules as in:

The amount of glucose required to prepare \(250 \mathrm{~mL}\) of \(\frac{\mathrm{M}}{20}\) aqueous solution is :
(Molar mass of glucose : \(180 \mathrm{~g} \mathrm{~mol}^{-1}\))

A compound X contains \(32 \%\) of A, \(20 \%\) of B and remaining percentage of C. Then, the empirical formula of \(\mathrm{X}\) is :
(Given atomic masses of A=64 ; B=40 ; C=32 u)

The highest number of helium atoms is in

1 gram of sodium hydroxide was treated with \(25 \mathrm{~mL}\) of \(0.75 \mathrm{~M} \mathrm{~HCl}\) solution, the mass of sodium hydroxide left unreacted is equal to

The density of 1 M solution of a compound 'X' is 1.25 g mL\(^{-1}\). The correct option for the molality of solution is (Molar mass of compound X = 85 g):

The right option for the mass of \(\mathrm{CO}_{2}\) produced by heating \(20 \mathrm{~g}\) of \(20 \%\) pure limestone is
(Atomic mass of \(\mathrm{Ca}=40\) )
$$\left[\mathrm{CaCO}_{3} \stackrel{1200 \mathrm{~K}}{\longrightarrow} \mathrm{C...

What fraction of Fe exists as Fe(III) in Fe0.96O ?
(Consider Fe0.96O to be made up of Fe(II) and Fe(III) only)

The density of the solution is 2.15 g mL\(-\)1, then mass of 2.5 mL solution in correct significant figures is :

What mass of 95% pure CaCO3 will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction?
CaCO3(s) + 2HCl(aq) \(\to\) CaCl2(aq) + Co2(g) + 2H2O(l)
[Calculate upto second place of decimal point]

In one molal solution that contains 0.5 mole of a solute, there is

An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is : [Atomic wt. of C is 12, H is 1]

The number of protons, neutrons and electrons in 17571Lu, respectively, are :

Which one of the following has maximum number of atoms?

The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s
process is :

A mixture of 2.3 g formic acid and 4.5 g oxalic
acid is treated with conc. H2SO4
. The evolved
gaseous mixture is passed through KOH
pellets. Weight (in g) of the remaining product
at STP will be

In which case is number of molecules of water
maximum?

Which of the following is dependent on temperature?

Suppose the elements X and Y combine to form two compounds XY2 and X3Y2. When 0.1 mole of XY2 weights 10 g and 0.05 mole of X3Y2 weighs 9 g, the atomic weights of X and Y are

A mixture of gases contains H2 and O2 gases in the ratio of 1 : 4 (w/w). What is the molar ratio of the two gases in the mixture ?

What is the mole fraction of the solute in a 1.00 m aqueous solution?

The number of water molecules is maximum in

If Avogadro number NA, is changed from 6.022 \(\times\) 1023 mol\(-\)1 to 6.022 \(\times\) 1020 mol\(-\)1, this would change

What is the mass of the precipitate formed when 50 mL of 16.9% solution of AgNO3 is mixed with 50 mL of 5.8% NaCl solution ? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5

1.0 g of magnesium is burnt with 0.56 g O2 in a closed vessel, Which reactant is left in excess and how much ? (At. wt. Mg = 24, O = 16)

Equal masses of H2, O2 and methane have been taken in a container of volume V at temperature 27oC in identical conditions. The ratio of the volumes of gases H2 : O2 : methane would be

When 22.4 liters of H2(g) is mixed with 11.2 litres of Cl2(g), each at S.T.P. the moles of HCl(g) formed is equal to

In an experiment it showed that 10 mL of 0.05 M solution of chloride required 10 mL of 0.1 M solution of AgNO3, which of the following will be the formula of the chloriode (X stands for the symbol of the element other than chlorine)

6.02 \(\times\) 1020 molecules of urea present in 100 mL of its solution. The concentration of solution is

How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO3? The concentrated acid is 70% HNO3.

Which has the maximum number of molecules among the following ?

The number of atoms in 0.1 mol of a triatomic gas is (NA = 6.02 \(\times\) 1023 mol\(-\)1)

25.3 g of sodium carbonate, Na2CO3 is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ion, Na+ and carbonate ions, CO\({}_3^{2 - }\) are respectively (Molar mas...

10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be

What volume of oxygen gas (O2) measuread at 0oC and 1 atm, is needed to burn completely 1 L of propane gas (C3H8) measured under the same conditions ?

How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g HCl ?

An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be

An element, X has the following isotopic composition:
200X : 90%  199X : 8.0%  202X : 2.0%
The weighted average atomic mass of the naturally occuring element X is closest to

Concentrated aqueous sulphuric acid is 98% H2SO4 by mass and has a density of 1.80 g mL\(-\)1. Volume of acid required to make one litre of 0.1 M H2SO4 solution is

The mole fraction of the solute in one molal aqueous solution is

The maximum number of molecules is present in

Which has maximum molecules?

2.5 litre of 1 M NaOH solution is mixed with another 3 litre of 0.5 M NaOH solution. Then find out molarity of resultant solution.