Question
What is the modern basis of atomic mass?
✓
Answer
Nowadays the atomic mass is determined according to $C -12$ standard. According to this, the atomic number of an element is the number from which it is known that any atom is how much heavier than
$\frac{1}{12}$ part of $C -12$. Hence one atomic mass unit $\frac{1}{12}^{\text {th }}$
part of mass of $C -12$.
$
1 amu=1.66056 \times 10^{-24} gm
$
$\frac{1}{12}$ part of $C -12$. Hence one atomic mass unit $\frac{1}{12}^{\text {th }}$
part of mass of $C -12$.
$
1 amu=1.66056 \times 10^{-24} gm
$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
What are the possible structures for a carboxylic acid with a molecular formula $\mathrm{C}_4 \mathrm{H}_8 \mathrm{O}_2$ and label each C atom as $\mathrm{sp}, \mathrm{sp}^2$ and $\mathrm{sp}^3$ ?
→Account for the following observations:
$\mathrm{AlCl}_3$ is a Lewis acid.
→$\mathrm{AlCl}_3$ is a Lewis acid.
Write the IUPAC name of the following compounds :
Which of the elements Na, Mg, Si and P would have the greatest difference between the first and second ionisation enthalpies? Briefly explain your answer.
In a reaction
$\mathrm{A}+\mathrm{B}_2 \rightarrow \mathrm{AB}_2$
Identify the limiting reagent, if any, in the following reaction mixtures.
100 atoms of A + 100 molecules of B.
→$\mathrm{A}+\mathrm{B}_2 \rightarrow \mathrm{AB}_2$
Identify the limiting reagent, if any, in the following reaction mixtures.
100 atoms of A + 100 molecules of B.
Which of the following compounds will show cis-trans isomerism?
1. $\left( CH _3\right)_2 C = CH - C _2 H _5$
2. $CH _2= CBr _2$
3. $C _6 H _5 CH = CH - CH _3$
4. $CH _3 CH = CCl CH { }_3$
→1. $\left( CH _3\right)_2 C = CH - C _2 H _5$
2. $CH _2= CBr _2$
3. $C _6 H _5 CH = CH - CH _3$
4. $CH _3 CH = CCl CH { }_3$
How would you explain the following observations?
BeO is almost insoluble but $\mathrm{BeSO}_4$ is soluble in water
→BeO is almost insoluble but $\mathrm{BeSO}_4$ is soluble in water
Determine the value of $\Delta \mathrm{H}$ and $\Delta \mathrm{U}$ for the reversible isothermal evaporation of 90.0 g of water at $100^{\circ} \mathrm{C}$. Assume that water vapour behave as an ideal gas and heat of evaporation of water is $540 \mathrm{cal}\left(\mathrm{R}=2.0 \mathrm{cal} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right)$.
→The equilibrium constant at $25^{\circ} \mathrm{C}$ for the process $\mathrm{CO}^{3+}(\mathrm{aq})+6 \mathrm{NH}_3(\mathrm{aq}) \rightleftharpoons\left[\mathrm{CO}\left(\mathrm{NH}_3\right)_6\right]^{3+}(\mathrm{aq})$ is $2.5 \times 10^6$. Calculate the value of $\Delta \mathrm{G}^{\circ}$ at $25^{\circ} \mathrm{C}\left(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right)$. In which direction is the reaction spontaneous under standard conditions?
→The species: $\text{H}_2\text{O}$, $\text{HCO}_3^-,$ $\text{HSO}_4^-$ and $\text{NH}_3$ can act both as Brönsted acids and bases. For each case give the corresponding conjugate acid and base.
→