The composition of a sample of wustite is $$ Fe_{0.95} O_{1.00}. $$ What is the percentage of  Fe(III) in the sample?

$$1.0\ g$$ of $$Mg$$ is burnt with $$0.28\ g$$ of $$O_{2}$$ in a closed vessel. Which reactant is left in excess and how much?

Percentage of oxygen in urea is about :

A sample of clay contains $$50\%$$ silica and $$10\%$$ water. The sample is partially dried by which it loses $$8\ g$$ water. If the percentage of silica in the partially dried clay is $$52$$, what is the percentage of water in the partially dried clay?

Compound Q contains $$40\%$$ carbon by mass.
What could Q be?
$$1$$. glucose, $$C_6H_{12}O_6$$
$$2$$. starch, $$(C_6H_{10}O_5)_n$$
$$3$$. sucrose, $$C_{12}H_{22}O_{11}$$.

A mixture of $$He(4)$$ and $$Ne(20)$$ in a $$5-$$litre flask at $$300\ K$$ and $$1$$ atm weighs $$4\ g$$. The mole $$\%$$ of $$He$$ is

What is involved in $$CO_2$$ and $$CH_4$$ inclusion?

A certain mixture of $$MnO$$ and $$MNO_2$$ contains $$66.6\ mol$$ per cent of $$MnO_2$$. What is the approximate mass percent of $$Mn$$ in it? $$(Mn=55)$$  

A sample of impure cuprous oxide contains $$66.67\%$$ copper, by ,mass. What is the percentage of pure $$Cu_2O$$ in the sample? $$(Cu=63.5)$$ 

What percentage of hydrogen fluoride molecules is trimerized?