Heena Sharma, Shubhankat Vats and, Rashmi Gupta Solutions for Chapter: Atoms and Molecules, Exercise 6: Challengers*

Which of the following represents a correct chemical formula? Name it.

a. $\mathrm{CaCl}$

b. ${\mathrm{BiPO}}_4$

c. ${\mathrm{NaSO}}_4$

d. $\mathrm{NaS}$

Four students $\mathrm{A},\mathrm{}\mathrm{B},\mathrm{}\mathrm{C}$ and $\mathrm{D}$ verified the law of conservation of mass by performing a chemical reaction between barium chloride and sodium sulphate. All of them took $107.2\mathrm{}\mathrm{g}$ barium chloride solution and $116.1\mathrm{}\mathrm{g}$ of sodium sulphate solution and mixed them in the beaker of mass $150\mathrm{}\mathrm{g}$. They reported their results as follows:

In a chemical reaction $10.6\mathrm{}\mathrm{g}$ of sodium carbonate reacted with $12\mathrm{}\mathrm{g}$ of ethanoic acid. The products were $4.4\mathrm{}\mathrm{g}$ carbon dioxide, $1.8\mathrm{}\mathrm{g}$ of water and sodium ethanoate. The mass of sodium ethanoate formed is

During an experiment, hydrogen $\left({\mathrm{H}}_2\right)$ and oxygen $\left({\mathrm{O}}_2\right)$ gases are reacted in an electric arc to produce water as follows: $2\mathrm{H}+{\mathrm{O}}_2\stackrel{\mathrm{E}\mathrm{l}\mathrm{e}\mathrm{c}\mathrm{t}\mathrm{r}\mathrm{i}\mathrm{c}\mathrm{i}\mathrm{t}\mathrm{y}}{\to }2{\mathrm{H}}_2\mathrm{O}$
The experiment is repeated three times and data tabulated as shown below:

Nitrogen and hydrogen combine together to form ammonia.
${\mathrm{N}}_2+3{\mathrm{H}}_2\to 2{\mathrm{N}\mathrm{H}}_3$
$\left[\mathrm{R}\mathrm{e}\mathrm{l}\mathrm{a}\mathrm{t}\mathrm{i}\mathrm{v}\mathrm{e} \mathrm{a}\mathrm{t}\mathrm{o}\mathrm{m}\mathrm{i}\mathrm{c} \mathrm{m}\mathrm{a}\mathrm{s}\mathrm{s}\mathrm{e}\mathrm{s} \mathrm{o}\mathrm{f} \mathrm{N}=14\mathrm{u},\mathrm{H}=1\mathrm{u}\right]$
The mass of nitrogen and hydrogen which combine together to form $6.8\mathrm{}\mathrm{g}$ ammonia is

Which of the following correctly represents $360\mathrm{}\mathrm{g}$ of water?
I. $2$ moles of ${\mathrm{H}}_2\mathrm{O}$
II. $20$ moles of water
III. $6.022\times {10}^{23}$ molecules of water
IV. $1.2044\times {10}^{25}$ molecules of water

$3.42\mathrm{}\mathrm{g}$ of glucose are dissolved in $18\mathrm{}\mathrm{g}$ of water in a beaker. The number of oxygen atoms in the solution is

Which of the following contains the maximum number of molecules?