Question

What mass of sodium oxide will be formed by burning 20g of sodium in the air?
I don't get how to get to the answer which is is 27g

Answer 1

Sodium(Na) = 23, Oxygen(O) = 16

Now,

4Na + 02 ----> 2Na2O

4(23) + 2(16) -------> 2[2(23)+16]

92+ 32 --------> 2(46+16)

92u+ 32u -------> 2(62)

92u + 32u -----> 124u

92g + 32g -------> 124g

92g of sodium gives 124g of sodium oxide ----(1)

Therefore, 20g of gives xg of Sodium oxide-----(2)

Now, (2)/(1)

20/92= x/124

x = 20×124/92

x = 26.9

x= 27g

Therefore,

20g of sodium gives 27g g of Sodium oxide

Answer 2

HEY BUDDY UR ANSWER...

.

sodium + oxygen arrow sodium oxide.

4Na(s) + O2(g) arrow 2Na2O(s)

Use the big numbers to find the proportion of reactant to product.

4Na makes 2Na2O, so 2Na makes 1Na2O,

so the proportion is 2 to 1.

2) Divide the RFM of the product

by the RAM of the reactant.

RFM of Na2O is (2 x 23) + (1 x 16) = 62.

RAM of Na = 23.

62 ÷ 23 = 2·696.

3) Multiply the number in 2 by both the

proportion and the mass in grams of the reactant.

The proportion is 2 to 1, or 1 to 0·5.

The mass of reactant is 20 g.

The mass of product is 2·696 x 0·5 x 20 g,

= 26·96 g.

So, burning 20 g of sodium in air will make 26·96 g of sodium oxide.

That is approximately 27 gm which is the answer.

.

HOPE THIS HELPS...