HELP ME PLEASE!!!! I NEEDZ HELP!!!

Suppose 83.0 mL. of dioxygen gas are produced by this reaction, at a temperature of 70.0 °C and pressure of exactly I atm. Calcu

Nastasia [14]

Answer:

m = 0.3249 g

Explanation:

First, I'm assuming you have a reaction of mercury(II) oxyde descomposition. If this is the case, then the equation to use is the following:

HgO ---------> Hg + O2

Balancing the equation:

2HgO ----------> 2Hg + O2

This means that 2 moles of HgO reacts to produce 1 mole of O2, so, we first calculate the moles of O2, then, the moles of HgO and finally the mass:

We have the volume of O2, the pressure and temperature, so let's use the ideal gas equation:

PV = nRT

Solving for n:

n = PV/RT

R: 0.082 L atm / K mole

T = 70 + 273 = 343 K

V = 83 / 1000 = 0.083 L

Calculating n:

n = 1 * 0.083 / 0.082 * 343

n = 0.003 moles

as stated before, 2 moles of HgO reacts with 1 mole of oxygen so:

2 moles HgO = 1 moles O2

moles HgO = moles O2 / 2

moles HgO = 0.003 / 2 = 0.0015 moles

Finally, to calculate the mass:

m = n * MM

the molar mass of HgO is 216.59 g/mol, so replacing:

m = 0.0015 * 216.59

m = 0.3249 g

3 0

3 years ago

Is it true or false that atoms form bonds by sharing physical properties

anygoal [31]

False. atoms form bonds in different ways with their electrons. in ionic bonds, atoms donate electrons and in covalent bonds, atoms share electrons

4 0

3 years ago

What is atomic mass, atomic number, isotopes and how are all these terms related to each other?

Airida [17]

Atomic mass deals with the number of protons and neutrons added together, atomic number deals with protons only, though isotopes can be explained like this, say you had a hydrogen atom it's one proton and one electron if you add a neutron to it, the hydrogen becomes Deuterium which is a isotope of hydrogen it's the same atom just a neutron added to it for a different atomic mass if only slightly changed

8 0

3 years ago

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Value of Δ H ∘ rxn for the equation NH 3 ( g ) + 2 O 2 ( g ) ⟶ HNO3 ( g ) + H 2 O ( g )

koban [17]

Answer: - 894.6 kJ/mol.

Explanation:

Hess law is states that the changes in enthalpies in a chemical reactions is independent of the pathway between the initial and final states.

∆H is the change in the sum of the internal energy of a system.

We are to find the Value of ΔH°(rxn) for the equation:

NH3 (g) + 2 O2 (g) ⟶ HNO3 (g) + H2O (g). ----------------------------------(**).

From the series of equations given;

==> 4NH3 (g) + 5O2 (g) -------->4 NO(g) + 6H2O (l). ∆H = -1166.0 kJ/mol.--------------------------------------(1).

===> 2NO(g) + O2 (g) ------> 2NO2 (g). ∆H = -116.2 kJ/mol.---------------(2).

===> 3NO2 (g) + H2O (l) ---------> 2HNO3 (aq) + NO (g). ∆H = -137.3 kJ/mol.-------------------------------------(3).

The first thing to do is to multiply equation (2) by 3. Also, multiply equation (3) by 2. This will give us equation (4) and (5) respectively.

6NO + 3 O2 ----------------> 6NO2. ∆H= 3 × (-116.2 kJ/mol) = -348.6 kJ/mol. ------------------------------------(4).

6NO2 + 2 H2O ----------------> 4HNO3 + 2 NO. ∆H= 2 × (-137.3kj/mol) = -274.6 kJ/mol ---------------------------(5).

Next, add equations (4) and (5) to give;

4NO +3O2 +2H2O -------------> 4HNO3. ∆H = -623.2 kJ/mol. -----(6).

Add this equation to the equation (1) from above, we have;

4NH3 + 8O2 --------------> 4HNO3 + 4H2O. ∆H= -1789.2 kJ/mol. --------(7).

Then, divide the equation (7) above by 2 to give us back the equation (**).

NH3 (g) + 2 O2 (g) ⟶ HNO3 (g) + H2O (g). ∆H= -894.6 kJ/mol.

Δ H^∘ (rxn)= - 894.6 kJ/mol.

5 0

3 years ago

What is the mass number of an isotope

makkiz [27]

<span>The mass number given on the periodic table is a weighted average of all the isotopes. You get the exact mass of an isotope by adding the protons(atomic number) to the number of neutrons in that isotope.</span>

8 0

3 years ago

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