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Answer: The pressure of the gas is 0.225 atm.
Explanation: To calculate the pressure of the gas, we use Boyle's Law.
Boyle's Law states that pressure is inversely proportional to the volume of the gas at constant temperature.
Mathematically,

Or,

where,
are the initial pressure nd volume.
are the final pressure andvolume
Initial conditions:

Final conditions:

Conversion factor: 1L = 1000mL
Putting values in above equation, we get:

Answer:The isotope is Carbon-12 and its atomic mass is 12.
Explanation:
Mass number is the total number of protons and neutrons in a nucleus.
Atomic number is the number of protons in the nucleus of an atom.
An isotope of a chemical element is an atom that has a different mass number but the same atomic number as the element. The difference in mass number is from the number of neutrons (that is, a greater or lesser atomic mass) than the standard for that element.
Carbon-12 is an isotope of carbon it has 6 neutrons and 6 protons, giving it a mass number of 12 and atomic number of 6. Carbon-12 is a stable isotope of carbon, it has the same mass number and atomic number as carbon.
4Fe + 3O2 → 2Fe2O3
i believe this is the answer
> How many valence electrons does a helium atom have?
The electron configuration of Helium is simply 1s2. We see
that its outermost shell is the s shell and it contains 2 electrons, therefore
the number of valence electrons is also 2.
> What is the formula of the ion formed when potassium
achieves noble-gas electron configuration?
Potassium has a electron configuration of [Ar] 4s1. To
have an electron configuration of only [Ar] which is a noble gas, the one electron
from 4s1 should be removed, hence:
<span>K+</span>