Water is H2O but I'm not sure about solids.
207 is the mass number. 82 would be the atomic number
A compound is a pure substance formed by the chemical combination of two or more different elements.
A compound may be splitted into simpler substances by chemical reactions, and has different properties to those of the elements that form it.
The composition of a compound is fixed: every piece of a compound has the same kind of atoms, bonded in the same way and proportion.
Some examples of compounds are H₂O, NaCl, H₂O₂, CH₃COOH. As you see, they have a chemical formula which states the kind and number of the atoms that form them.
They are different to mixtures, which are formed by two or more compounds, in a variable proportion, and can be separated by physical media. Some examples of mixtures are the solutions (e.g. NaCl dissolved in H₂O), and some solid mixtures (e.g. a mixture of marbles and sand).
Taking into account the scientific notation, the result of the subtraction is 6.5×10⁵.
<h3>Scientific notation</h3>
First, remember that scientific notation is a quick way to represent a number using powers of base ten.
The numbers are written as a product:
a×10ⁿ
where:
- a is a real number greater than or equal to 1 and less than 10, to which a decimal point is added after the first digit if it is a non-integer number.
- n is an integer, which is called an exponent or an order of magnitude. Represents the number of times the comma is shifted. It is always an integer, positive if it is shifted to the left, negative if it is shifted to the right.
<h3 /><h3>Subtraction in scientific notation</h3>
You want to subtract two numbers in scientific notation. It should be noted that when the numbers to be added do not have the same base 10 exponent, the base 10 power with the highest exponent must be found. In this case, the highest exponent is 5.
Then all the values are expressed as a function of the base 10 exponent with the highest exponent. In this case: 5.00×10⁴=0.500×10⁵
Taking the quantities to the same exponent, all you have to do is subtract what was previously called the number "a". In this case:
7.00×10⁵ - 0.500×10⁵= (7.00- 0.500)×10⁵= 6.5×10⁵
Finally, the result of the subtraction is 6.5×10⁵.
Learn more about scientific notation:
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Answer is: quark.
Quark is a type of elementary particle and a fundamental constituent of matter.
Quarks form composite hadrons (protons and neutrons). Protons and neutrons are in the nucleus of an atom.
Hadrons include baryons (protons and neutrons) and mesons.
There are six types of quarks: up, down, strange, charm, bottom, and top.
