Question

If 21.7 mL Na, with a density of 0.97 g/mL, react with excess oxygen gas, how many moles of sodium oxide can be formed?

unbalanced equation: Na + O2 “yields”/ Na2O

0.458 mol Na2O

0.487 mol Na2O

1.83 mol Na2O

1.95 mol Na2O

(I know this is chem but no one is alive in that section so I really, really am just desperate and need someone to help me out. Please)

Answer 1

use the equation

2Na + O2 = Na2O

2 moles of sodium give one mole of sodium oxise

Answer 2

sorry i havent balanced the equation

its

4 Na + O2 = 2Na2 O


so 2 moles of sodium give 1 mole of sodium oxide

Answer 3

Yeah I did that. And for the stoichiometry part, I did:

21.7 mL Na * 1 mol Na/22.989 g Na * 2 mol O/4 mol Na * 0.97/1 mol

Answer 4

But I'm not sure what the answer would be. I'm not even sure if my work is correct or not

Answer 5

Do you know what the answer is @cwrw238 ?

Answer 6

I think it's A

Answer 7

long time since i've done this stuff

first i think you must convert 21.7 mls of Na to mole

21.7 mls of 0.97 g / ml

= 21.7 * 0.97 g = 21.31 g sodium

Answer 8

1 mole of sodium = 23 g right?

Answer 9

yes

Answer 10

so thats 0.9265 moles of sodium

so if 2 moles gives 1 mole of sodium oxide
then we will get

0.9265 / 2 = 0.4633 moles of the oxide

Answer 11

which is close to A..

Answer 12

i cant see where i;ve made any mistake...

Answer 13

is 23 g right for 1 mole of Na?

Answer 14

22.99 is given on website - that will make very little difference

Answer 15

oh - can see my mistake

21.7 * 0.97 = 21.049 g

= 0.916 moles

giving 0.916 = 0.458

Answer 16

yes its A
ok/

Answer 17

I must have pressed wrong key on my calculator lol

Answer 18

0.916 / 2 = 0.458

Answer 19

do you follow my method ok?

Answer 20

oh hey sorry for replying so late. And yes, thank you

Answer 21

yw