A compound of nitrogen and hydrogen is 87.4% nitrogen by mass. Its empirical formula is:
ANH
BNH2
CNH3
DN2H
Answer & Solution
Correct answer: B. NH2
1. Take 100 g: 87.4 g nitrogen and $100-87.4=12.6$ g hydrogen.
2. Divide by relative atomic masses: nitrogen $\dfrac{87.4}{14}=6.243$, hydrogen $\dfrac{12.6}{1}=12.6$.
3. Divide both by the smaller: nitrogen $1$, hydrogen $\dfrac{12.6}{6.243}=2.02$.
4. The simplest whole-number ratio is therefore $1:2$.
5. The empirical formula is NH₂. Forgetting to subtract from 100 to get the hydrogen percentage is the usual first slip.
_Source: NECTA ACSEE 2023 Chemistry 132/1, Question 1: Gases_
Related questions
A gas collected over water at 1 atm has water vapour pressure 17.5 mmHg. The pressure of tThe same compound has density 0.977 g/L at 710 mmHg and 100°C, giving $M_r\approx32$. Its To find the volume a swallowed drop of liquid oxygen occupies as gas at 37°C, the order ofThe syringe illustration for Boyle's law holds the temperature at:A sealed balloon is used to illustrate Charles's law because it holds:Avogadro's law implies that at fixed temperature and pressure a gas's volume depends on:Effusion differs from diffusion because effusion specifically involves passage through:Pressure being inversely proportional to area means that the same force on a smaller area