Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by $N_0$ .

Also, it is the number of particles in exactly 12.000 g of isotope carbon 12.

Avogadro constant:-

$N_a=6.023\times 10^{23}$

Hence,

Mass of $XeF_n$ = 131.293+ n18.998 g

So,

$6.023\times 10^{23}$ molecules have a mass of 131.293+ n18.998 g

Also,

$1$ molecules have a mass of $\frac{(131.293+ n18.998)}{6.023\times 10^{23}}$ g

So,

$5.0\times 10^{20}$ molecules have a mass of $\frac{(131.293+ n18.998)}{6.023\times 10^{23}}\times 5.0\times 10^{20}$ g

Also, given mass = 0.172 g

Thus,

$\frac{(131.293+ n18.998)}{6.023\times 10^{23}}\times 5.0\times 10^{20}=0.172$

$\frac{18.998n+131.293}{1204.6}=0.172$

$18.998n+131.293=207.1912$

$n=\frac{75.8982}{18.998}=4$

Thus, value of n is 4.

4 0

2 years ago

A 10.11 g sample of NaBr contains 22.34 % Na by mass. Considering the law of constant composition (definite proportions), how ma

Ksenya-84 [330]

Answer:

$1.58\ \text{g}$

Explanation:

10.11 g sample of $NaBr$ contains 22.34% $Na$ by mass

According to the law of constant composition the if one sample of $NaBr$ has 22.34% of $Na$ by mass then any other sample of $NaBr$ will have the same percentage of the amount of $Na$ .

For a sample of 7.09 g we have

$7.09\times \dfrac{22.34}{100}=1.583906\approx 1.58\ \text{g}$

The mass of sodium in the required sample is $1.58\ \text{g}$ .

8 0

2 years ago

Which has more energy, 500g of ice or 500g of steam

liraira [26]

Answer:

Steam because steam pushes out and ice stays dormant.

Explanation:

5 0

2 years ago