Answer:
Cracking.
Explanation:
A chemical reaction can be defined as a reaction in which two or more atoms of a chemical element react to form a chemical compound. An example of a chemical reaction involving hydrocarbons is cracking.
Hydrocarbon can be defined as an organic compound that comprises of hydrogen and carbon only.
In Organic chemistry, cracking refers to the process of lowering the boiling point of a heavy, complex or long-chain hydrocarbon such as kerogens by exposing it to different environmental treatments such as hydrogen enriched catalysts, pressure or high temperatures, in order to produce smaller, lighter and more useful molecules (alkanes and alkenes) such as gasoline, diesel fuel, etc.
Answer:
- <em><u>Mendeleev produced the first orderly arrangement of known elements.</u></em>
- <em><u>Mendeleev used patterns to predict undiscovered elements.</u></em>
Explanation:
- <u>Mendeleev produced the first orderly arrangement of known elements and used patterns to predict the undiscovered elements.</u>
Those two statments are true.
For the time being there were some 62 known elements. Before Medeleev some schemes to order part of the elements were proposed, but Medeleev showed the relationship between the atomic mass and the properties of the elements (supports second choice). This arrangement is known as the periodic table.
More importantly, Mendeleev predicted correctly the existance and properties of unknown elements, which is his major contribution: he left blanket spaces which where gradually filled when new elements where discovered (this supports the fourth choice).
The first modern chemistry book was written by Antoine Lavoisier (this discards first option).
Mendeleev ordered the elements by increasing mass number (this discards third choice), which was corrected later by the scientist Henry Moseley, who ordered the elements by increasing atomic number (number of protons).
Isotopes were not known by Mendeleev times, so this discards the last option.
Answer:
Electricity. Coal alone provides half the electricity in the United States. ...
Heating. Oil and natural gas are commonly used for heating homes as well as providing heat for industrial applications.
Transportation. Oil supplies 99 percent of the energy for cars in the form of gasoline and diesel. ...
Limits. ...
Considerations.
Explanation:
<h2>Answer : </h2>
<h3>D. HETEROGENEOUS MIXTURE </h3>
HOPE IT HELP ❤️
Oxygen has 8 electrons. On the outer ring, it has 6 valance electrons. It need 2 more valance electrons to be stable.
