Question

52.4 g of hydrogen are ignited with 4 g of oxygen.
The weight of water formed is -
(1) 0.5 g (2) 3.5 g (3) 4.5 g (4) 2.5 g​

Answer 1

Ans= 3) 4.5g

• The chemical formula of water is H2O
• This means that 2 atoms of hydrogen reacts with 1 atom of oxygen to form 18g of water.
• So, 2g of hydrogen = 16g of oxygen.

So, 4g of oxygen = 2/4g of hydrogen

= 0.5g of hydrogen

Therefore mass of water

=4g + 0.5g

=4.5g

Answer 2

Answer:

"Mass"~=4.5*g

Mass

≅

4.5

⋅

g

Explanation:

We need (i), a stoichiometric equation,

H_2(g) + 1/2O_2(g) rarr H_2O(l)

H

2

(

g

)

+

1

2

O

2

(

g

)

→

H

2

O

(

l

)

.

We have (4*g)/(32.0*g*mol^-1)=1/8*mol "dioxygen gas".

And (4*g)/(2.0*g*mol^-1)=2*mol "dihydrogen gas".

Clearly, the "dioxygen gas" is present in DEFICIENCY, and O_2 is the limiting reagent.

Given the equation, we can make at most 1/4*mol of water, i.e. a mass of 1/4*cancel(mol)xx18.01*g*cancel(mol^-1)=??*g