The element used in advertising signs is neon.
Answer:

Explanation:
Mol of NaI = 0.405 mol
Molarity of solution = 0.724 M
Molarity is given by

The required volume is
.
Answer:
203 grams
Explanation:
<em>It is known that 1.0 mole of a compound contains Avogadro's number of molecules (6.022 x 10²³).
</em>
<em><u>Using cross multiplication:</u></em>
1.0 mol contains → 6.022 x 10²³ molecules.
??? mol contains → 7.2 x 10²⁴ molecules.
∴ The no. of moles of (6.3 x 10²⁴ molecules) of NH₃ = (1.0 mol)(7.2 x 10²⁴ molecules)/(6.022 x 10²³ molecules) = 11.96 mol.
<em>∴ The no. of grams of NH₃ present = no. of moles x molar mass </em>= (11.96 mol)(17.0 g/mol) = <em>203.3 g ≅ 203.0 g.</em>
At a constant temperature and pressure, liquids retain their volume
Answer:
9.69g
Explanation:
To obtain the desired result, first let us calculate the number of mole of N2 in 7.744L of the gas.
1mole of a gas occupies 22.4L at stp.
Therefore, Xmol of nitrogen gas(N2) will occupy 7.744L i.e
Xmol of N2 = 7.744/22.4 = 0.346 mole
Now let us convert 0.346 mole of N2 to gram in order to obtain the desired result. This is illustrated below:
Molar Mass of N2 = 2x14 = 28g/mol
Number of mole N2 = 0.346 mole
Mass of N2 =?
Mass = number of mole x molar Mass
Mass of N2 = 0.346 x 28
Mass of N2 = 9.69g
Therefore, 7.744L of N2 contains 9.69g of N2