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4 years ago

An isotope of an element, atomic number Z, has a mass number 2z+4. How many neutrons are there in the nucleus of the element?

2 answers:

8 0

A) Z + 4

In the actual atom, half of the nucleus would be protons and the other half neutrons, hence the 2z. The additional four in the expression must be neutrons because adding protons would change the element all together.

Wewaii [24]4 years ago

7 0

Answer:

A) Z+4

Explanation:

Atomic number of the isotope = Z

Mass number of the isotope = 2Z+4.

Atomic number = Number of protons in the atom = Number of electrons in the atom

Mass number = Number of protons in the atom + Number of neutrons in the atom

Hence number of neutrons = Mass number - Number of protons

= 2Z + 4 - Z = Z + 4

Hence the required answer to the question is represented by option A which is Z + 4.

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What is the molar mass for FeBr3

AleksAgata [21]

Mass of Iron (Fe): 55.845Mass of Bromine (Br): 79.904
You need to multiply the mass of Br by 3 because there are 3 Bromine atoms.
(79.904)(3)+ 55.845= 239.712+55.845 = 295.557 g/mol

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3 years ago

If 12.6 grams of iron (III) oxide reacts with 9.65 grams of carbon monoxide to produce 7.23 g of pure iron, what are the theoret

Mariana [72]

The balanced equation is Fe₂O₃ + 3 CO = 2 Fe + 3 CO₂.
Next step is to convert everything to moles.
12.6g Fe₂O₃ x (1 mol Fe₂O₃ / 159.7g Fe₂O₃) = 0.07890 mol Fe₂O₃
9.65g CO x (1 mol CO / 28.01g CO) = 0.3445 mol CO
The third step is to determine the limiting and excess reactants.
0.07890 mol Fe₂O₃ x (3 mol CO/1 mol Fe₂O₃) = 0.2367 mol CO
Therefore Fe₂O₃ is the limiting reagent while CO is in excess.

0.07890 mol Fe x (2 mol Fe(s) / 1 mol Fe₂O₃) = 0.1578 mol Fe(s)
0.1578 mol Fe x (55.84g Fe / mole Fe) = 8.812g Fe is the theoretical yield
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3 years ago

What is true of a gas

velikii [3]

Answer:

did you have options, cause if you did chose something alond the lines of

Explanation:

A real gas is a gas that does not behave as an ideal gas due to interactions between gas molecules. A real gas is also known as a nonideal gas because the behavior of a real gas in only approximated by the ideal gas law.

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3 years ago

Which comppund contains both ionic and covalent bonds

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Answer:

potassium contains both Ionic and covalent bonds

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2 years ago

Predict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the boiling of water, and exp

Sedbober [7]

Answer:

ΔH > 0; ΔS >0; ΔG = 0

Not spontaneous when T < 100 °C;

Equilibrium when T = 100 °C

Spontaneous when T > 100 °C

Step-by-step explanation:

The process is

H₂O(ℓ) ⇌ H₂O(g)

ΔH > 0 (positive), because we must add heat to boil water

ΔS > 0 (positive), because changing from a liquid to a gas increases the disorder

ΔG = 0, because the liquid-vapour equilibrium process is at equilibrium at 100 °C

ΔG = ΔH – TΔS

Both ΔH and ΔS are positive.

If T = 100 °C, ΔG =0. ΔH = TΔS, and the system is at equilibrium.

If T < 100 °C, the ΔH term will predominate, because T has decreased below the equilibrium value.

ΔG > 0. The process is not spontaneous below 100 °C.

If T > 100 °C, the TΔS term will predominate, because T has increased above the equilibrium value.

ΔG < 0. The process is spontaneous above 100 °C.

4 0

3 years ago