Question

4 g of hydrogen reacts with 20 g of oxygen to form
water. The mass of water formed is
(1) 24 g
(2) 36 g
(3) 22.59
(4) 40g​

Answer 1

Answer:

$\bigstar$ Given:

⇒ 4 g of hydrogen reacts with 20 g of oxygen to form water.

$\bigstar$ To Find:

⇒ The mass of water formed is

$\bigstar$ Solution:

The reaction is gives as,

$\blue\boxed{{\boxed{\sf H_2 + \frac{1}{2} O_2 \implies H_2O}}}$

⇒ 1 mole of  $\sf H_2$ requires 0.5 moles of  $\sf O_2$

∴ 1.25 moles of $\sf H_2$ requires 0.625 moles of $\sf O_2$

Since, $\sf O_2$ acts as a limiting reagent

⇒ 0.5 moles of  $\sf O_2$ gives 1 mole of  $\sf H_2O$

$\sf \therefore \;0.625\; moles \;of \;O_2\;gives \\\\\implies \dfrac{1*0.625}{0.5} \;moles\;of \;H_2O$

⇒ 0.625 moles of $\sf O_2$ gives 1.25 moles of $\sf H_2O$

Therefore,

Mass of $\sf H_2O$ formed is

$\implies \sf 1.25*18 = 22.5 \;grams$

∵ 18 is the molecular mass of $\sf H_2O$ (2 + 16 = 18)

Hence,

The mass of water formed is $\orange{\boxed{\sf 22.5\; grams}}$