Answer:
a.
can be made up of a combination of different elements.
Nylon is named as the most useful synthetic material. Nylon belongs to a family of materials called "polyamides."
Answer:
The answer is: the number of unpaired valence electrons
Explanation:
The valence electrons are the number of electrons present in outer shell of an atom that participate in chemical bond formation, if the outer shell is not completely filled.
Covalent bond formation occurs when two atoms contribute one valence electron each to form a bond. Thus the number of covalent bonds that an element can form, can be determined by the number of unpaired valence electrons.
Therefore, the nature and the number of bonds formed by the element and the chemical properties of the element can be determined by the number of valence electrons present in the outer shell of the element.
Answer:
They want to know how long it has been since it last erupted.
Explanation:
Scientists study a volcano's history to try to predict when it will next erupt. They also want to know the time span between its previous eruptions
Answer:
74.9%.
Explanation:
Relative atomic mass data from a modern periodic table:
- Ca: 40.078;
- C: 12.011;
- O: 15.999.
What's the <em>theoretical</em> yield of this reaction?
In other words, what's the mass of the CO₂ that should come out of heating 40.1 grams of CaCO₃?
Molar mass of CaCO₃:
.
Number of moles of CaCO₃ available:
.
Look at the chemical equation. The coefficient in front of both CaCO₃ and CO₂ is one. Decomposing every mole of CaCO₃ should produce one mole of CO₂.
.
Molar mass of CO₂:
.
Mass of the 0.400655 moles of 
expected for the 40.1 grams of CaCO₃:
.
What's the <em>percentage</em> yield of this reaction?
.
