Answer:
A. Because they are compounds, they cannot be pure substances.
Explanation:
The false statement from the given choices is that because they are compounds they cannot be pure substances. In fact, because they are compounds they are pure substances.
Pure substances are made up of elements and compounds and they have the following properties:
- All parts are the same throughout
- Composition is definite
- They cannot easily be separated or broken
- Separation by physical method is not easy
- They have unique sets of physical and chemical properties.
Answer:
Atomic mass of nitrogen = 14.0067 amu.
Explanation:
Isotopes can be defined as two or more forms of a chemical element that are made up of equal numbers of protons and electrons but different numbers of neutrons.
Generally, the isotopes of a chemical element have the same chemical properties because of their atomic number but different physical properties due to their atomic weight (mass number).
The two isotopes of nitrogen are nitrogen-14 and nitrogen-15.
Given the following data;
Relative abundance of N-14 = 99.63%
Atomic mass of N-14 = 14.003
Relative abundance of N-15 = 0.37%
Atomic mass of N-15 = 15.000
The atomic mass is;
14.003 × (99.63/100) + 15.000 × (0.37/100)
Atomic mass = 14.003 × (0.9963) + 15.000 × (0.0037)
Atomic mass = 13.9512 + 0.0555
Atomic mass = 14.0067 amu.
<em>Therefore, the atomic mass of nitrogen is 14.0067 amu. </em>
The atomic mass unit is presently based on assigning an exact integral mass (in amu) to an isotope of carbon.
<h3>What is the atomic mass?</h3>
The atomic mass is a measurement used in physics and chemistry to denote the average atomic mass of a given element which is measured in the atomic mass unit or amu.
In conclusion, the atomic mass unit is presently based on assigning an exact integral mass (in amu) to an isotope of carbon.
Learn more about the atomic mass here:
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By looking at the stochiometry, we can conclude that the ratio is 1 :1
2 moles of H2 react to form 2 moles of H2O
hope this helps
