Question

two samples of sodium chloride were decomposed into their constituent elements. one sample produced 6.98g of sodium and 10.7g of chlorine, and the other sample produced 11.2 g of sodium g and 17.3g of chlorine. are these results consistent with the law of definite proportion?

Answer 1

Element ratio in both the compounds is same.

Hence the results are consistent with the law of definite proportion.

Step-by-step explanation:

The law of definite proportion states that the elements will combine in a definite mole ration to form compounds.

Let us calculate the moles of sodium and chlorine produced from the decomposition of the two given samples.

Sample 1:

the mass of sodium = 6.98 g

moles of sodium =
`(mass)/(atomicmass) =(6.98)/(23)=0.30`

The mass of chlorine =10.7

moles of chlorine =
`(mass)/(atomicmass) =(10.7)/(35.5)=0.30`

The mole ratio = 1:1

Sample 2:

the mass of sodium = 11.2 g

moles of sodium =
`(mass)/(atomicmass) =(11.2)/(23)=0.0.49`

The mass of chlorine =10.7

moles of chlorine =
`(mass)/(atomicmass) =(17.3)/(35.5)=0.49`

The mole ratio = 1:1

Thus in both the compounds the mole ratio is same.

Hence the results are consistent with the law of definite proportion.

Answer 2

In law of definite proportions, all you need to show is how much one component reacts with another one on a unit weight basis. So let us try it here.
Sample 1: 6.98 g Na reacts with 10.7 g Cl, so 1 g Na will react with 10.7/6.98 = 1.53 g Cl Sample 2: same approach as above, 17.3/11.2 = 1.54 g Cl
So in both samples of NaCl, the sodium reacts with Cl in a definite proportion of 1:1.5 (rounded out).
There you have it.
p.s. you can do these calculations either on per g or per 100 g basis, ratios will remain the same.