Answer:
2. 
3. 
Explanation:
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2. In this case, we can evidence the problem by which volume and temperature are involved, so the Charles' law is applied to:

Thus, considering the temperatures in kelvins and solving for the final volume, V2, we obtain:

Therefore, we plug in the given data to obtain:

3. In this case, it is possible to realize that the 3.7 moles of neon gas are at 273 K and 1 atm according to the STP conditions; in such a way, considering the ideal gas law (PV=nRT), we can solve for the volume as shown below:

Therefore, we plug in the data to obtain:

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Answer:
currently model of the atom shows an atom that is mostly empty space. In the center is a small nucleus made of protons and neutrons. The nucleus contains nearly all the mass of an atom. Surrounding the nucleus is a cloud-like region with electrons moving too fast and too unpredictably for us to know their location
Explanation:
4X + 3O₂ = 2X₂O₃
n(X₂O₃)=0.02225 mol
m(X)=4.000 g
x - the molar mass of metal
m(X)/4x=n(X₂O₃)/2
x=m(X)/{2n(X₂O₃)}
x=4.000/{2*0.02225)=89.89 g/mol
X=Y (yttrium)
Answer: The density of the liquid is 
Explanation:
Density is defined as the mass contained per unit volume.
Given : Mass of the unknown liquid = 938 grams
Volume of the unknown liquid =
Putting in the values we get:
Thus the density of the liquid is
and the liquid is dimethyl sulfoxide.
N(H₂O)=1g÷18g/mol=0,055mol
N(H₂O)=0,055mol · 6·10²³ 1/mol (Avogadro number)= 3,33·10²² molecules.