Answer: How to calculate the mass percent by using these instructions
1.The molar mass is the mass of a given chemical element or chemical compound (g) divided by the amount of substance (mol).
2.The molar mass of a compound can be calculated by adding the standard atomic masses (in g/mol) of the constituent atoms.
Explanation:
To determine the empirical formula for the compound that contains <span>0.979 g Na, 1.365 g S, and 1.021 g O, we convert these to mole units. The molar masses to be used are:
Molar mass of Na = 23 g/mol
</span>Molar mass of S = 32 g/mol
Molar mass of O = 16 g/ mol
The number of moles is obtained using the molar mass for each element.
moles Na = 0.979 g Na/ 23 g/mol Na = 0.04256
moles S = 1.365 g Na/ 32 g/mol Na = 0.04265
moles O = 1.021 g O/ 16 g/mol Na = 0.06326
We then divide each with the smallest number of moles obtained.
Na: 0.04256/ 0.04256 = 1
S: 0.04265/ 0.04256 = 1.002 ≈ 1
O: 0.06326/ 0.04256 = 1.49 ≈ 1.5
We then have an empirical formula of NaSO₁.₅. However, chemical formulas must have only integers as subscripts, thus, we multiply each to 2. The empirical formula is then Na₂S₂O₃ also known as sodium thiosulfate.
Answer:
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1 mole of any gas under STP has volume 22.4 L.
Molar mass M(H2S) = 2M(H) + M(S)= 2*1.0 +32.1=34.1 g/mol
15g * 1mol/34.1g= 0.440 mol
0.440 mol*1L/22.4L= 9.85 L
<span> The volume of 15.0 grams of H2S at STP is 9.85 L.</span>
