Question

tec
im
2. Hydrogen and oxygen combine in
the ratio of 1:8 by mass to form
water. What mass of oxygen gas
would be required to react
completely with 3 g of hydrogen
gas?
3. Which postulate of Dalton's
atomic theory is the result of the
law of conservation of mass?
4. Which postulate of Dalton's
atomic theory can explain the law
of definite proportions?​

Answer 1

Answer:

when molecular hydrogen ( H²) and oxygen ( O²) are combined and allowed to react together ,energy is released and the molecules of hydrogen and oxygen can combine to from either water or hydrogen peroxide . these two processes are represented by the two chemical equations shown at right.

Answer 2

Answer:

The law of constant proportions states that in a chemical substance, the elements are always present in definite proportions by mass. Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water.

1g of hydrogen reacts with oxygen = 8g

Thus, in order to form water, 3 x 8 = 24 g of oxygen will react completely with 3 g of hydrogen gas.

Concept insight: Recall the law of constant proportions and then apply that in a chemical substance, the elements are always present in definite proportions by mass.

OR

2H

2

+O

2

→2H

2

O

4g 32g 36g

Since, 32 g of oxygen reacts with 4g of H

2

.

So, 3g of H

2

will require =

4

3×32

=24 grams of O

2