How many moles is 135 L of ammonia gas at STP

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 $N_0$ .

Avogadro constant:-

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

Let the molar mass of the element is x g/mol

So,

$6.023\times 10^{23}$ atoms have a mass of x g

Also,

$3.89\times 10^{24}$ atoms have a mass of $\frac{x}{6.023\times 10^{23}}\times 3.89\times 10^{24}$ g

This mass is equal to 848 g

So,

$\frac{x}{6.023\times 10^{23}}\times 3.89\times 10^{24}=848$

x= 131.3 g/mol

This mass correspond to xenon.

3 0

3 years ago

What mass of solute must be used to prepare 500ml of 0.100M aqueous sodium borate Na2B4O7 from solid hydrated sodium borate Na2B

motikmotik

0.000132 g of hydrated sodium borate (Na₂B₄O₇ · 10 H₂O)

Explanation:

First we need to find the number of moles of sodium borate (Na₂B₄O₇) in the solution:

molar concentration = number of moles / volume (L)

number of moles = molar concentration × volume (L)

number of moles of Na₂B₄O₇ = 0.1 × 0.5 = 0.05 moles

We know now that we need 0.05 moles of hydrated sodium borate (Na₂B₄O₇ · 10 H₂O) to make the solution.

Now to find the mass of hydrated sodium borate we use the following formula:

number of moles = mass / molar weight

mass = number of moles × molar weight

mass of hydrated sodium borate = 0.05 / 381 = 0.000132 g

Learn more about:

molar concentration

brainly.com/question/14106518

#learnwithBrainly

4 0

3 years ago