Some basic concepts of chemistry practice · Mixed difficulty

What volume of oxygen gas at NTP is necessary for complete combustion of $20 \mathrm{~L}$ of propane measured at $0^{\circ} \mathrm{C}$ and $760 \mathrm{~mm}$ pressure?

If ${\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4}$ ionises as ${\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4} + 2{\mathrm{H}_2}\mathrm{O} \to 2{\mathrm{H}_3}{\mathrm{O}^ + } + \mathrm{SO}_4^2$, then total number of ions produced by $\mathrm{0}\mathrm{.1}\;\mathrm{M}\;{\mathrm{H}_2}\mathrm{S}{\mathrm{O}_4}$ will be

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

One litre ${\mathrm{N}_2},\frac{7}{8}\mathrm{litre}\;{\mathrm{O}_2}$ and 1 litre $CO$ are taken in a mixture under indentical conditions of P and T. The amount of gases present in mixture is given by:

50 litres of water containing $\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2$ when converted into soft water required $22.2 \mathrm{~g} \mathrm{~Ca}(\mathrm{OH})_2$. Calculate the amount of $\mathrm{Ca}\left(\mathrm{HCO}_3\right)_2$ present per litre of hard water.

Weight of an atom of an element is $6.644 \times {10^{ - 23}}\;g$. What will be the number of g atom of that element in 40 kg?

The molecular mass of $\mathrm{CaSO}_4 \cdot 2 \mathrm{H}_2 \mathrm{O}$ is

(At. mass of Ca = 40, S = 32)

21.75g of $Mn{O_2}$ on reaction with HCl forms 2.8 L of $C{l_2}\left( g \right)$ at STP, the percentage purity of $Mn{O_2}$ is (atomic mass of Mn = 55u)
$Mn{O_2} + 4HCl \to MnC{l_2} + C{l_2} + 2{H_2}O$

$\mathrm{Cu}_2 \mathrm{S} \rightarrow \mathrm{Cu}^{2+}+\mathrm{SO}_3^{2-}$, if $\mathrm{M}$ is the molar mass of $\mathrm{Cu}_2 \mathrm{S}$, then its equivalent mass is given as

A gaseous alkane is exploded with oxygen.
The volume of $\text{O}_2$ for complete combustion to
the volume of $\text{CO}_2$ formed is in $7:4$ ratio. The
molecular formula of alkane is

Dopamine is a neurotransmitter, a molecule that serves to transmit message in the brain. The chemical formula of dopamine is $\mathrm{C}_8 \mathrm{H}_{11} \mathrm{O}_2 \mathrm{~N}.$ How many moles are there in $1 \mathrm{~g}$ of dopamine?

Statement-I: 12 parts by mass of carbon in $\mathrm{CO}$ and $\mathrm{CO}_2$ molecules combine with 16 and 32 parts by mass of oxygen.

Statement-II: A given compound always contains exactly the same proportion of elements by weight.

Boron has two isotopes boron-10 and boron-11 whose percentage abundances are $19.6 \%$ and $80.4 \%$ respectively. What is the average atomic mass of boron?

Often, while calculating, there is a need to convert units from one system to other. The method used to accomplish is called

Volume in $\mathrm{ml}$ of 11.2 volume strength $\mathrm{H}_2 \mathrm{O}_2$ required to exactly neutralize $20 \mathrm{ml}$ of $0.2 \mathrm{M}$ of $\mathrm{KMnO}_4$ in acid medium is

How many moles of ${H_2}S{O_4}$ are present in 4.9 g ${H_2}S{O_4}$