a. ELEMENT: A substance<span> that </span>cannot<span> be decomposed (</span>broken down<span>) </span>into simpler substances by ordinary chemical<span> means.</span>
Answer:
Here’s what I get.
Explanation:
- The atomic number is the number of protons in the nucleus of an atom.
- The number of protons determines the number of electrons.
- The number of electrons determines the chemical properties of the element,
Thus, the atomic number determines the identity of the element.
The atomic mass does not affect the chemical properties, so different isotopes of an element behave alike.
First find the number of moles of sulfur using dimensional analysis with avogadro’s number as the conversion factor. 4.2*10^24 atoms * (1 mol/6.022*10^23 atoms) = 7.0 mol sulfur. The molar mass of sulfur is 32.06 g/mol, which is found on the periodic table as sulfur’s (S) atomic weight. Use dimensional analysis again with the molar mass of sulfur as the conversion factor. 7.0 mol * 32.06 g/mol = 224.42 g sulfur. Since the problems gives us two significant figures, round the mass of sulfur to 220 grams, or 2.2 * 10^2 g.
The answer is D, medical diagnosis
