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3 years ago

Select all that apply. Any element can always be identified by its _____.

Chemistry

2 answers:

musickatia [10]3 years ago

5 0

Answer:

Any element can always be identified by its number of protons and atomic number.

Explanation:

All atoms are composed of a central nucleus in which there are particles with a positive electric charge, the protons, around which other particles with a negative electric charge that are electrons move. Thus, the atom is electrically neutral, since the positive charge of the protons is compensated by the negative charge of the electrons.

Atoms of different elements have different amounts of protons. The atomic number (which is identified by the letter Z) indicates the amount of protons that is present in the nucleus of an atom. This number is then responsible for defining the electronic configuration of the atom and the chemical properties of the element. Then it is possible to say that the number of protons in the nucleus, that is to say the atomic number Z, of an atom determines its identity. For this reason, the atomic number allows the ordering of the various chemical elements in the periodic table.

Finally, any element can always be identified by its number of protons and atomic number.

Gala2k [10]3 years ago

4 0

The answer is c. number of protons and d. atomic number. The proton number can identify an element. And also the atomic number is equal to the number of protons.

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The active ingredient in aspirin is acetylsalicylic acid. A 2.79 g sample of acetylsalicylic acid required 30.15 mL of 0.5137 M

vivado [14]

Answer:

Molar mass = 180 g/mol

Ka = 3.31x10⁻⁴

Explanation:

Because the acetylsalicylic is a monoprotic acid, it only leaves 1 mol of H⁺ in the reaction, so, it's necessary 1 mol of NaOH for each 1 mol of acetylsalicylic acid. The number of moles of NaOH is the volume, in L, multiplied by the concentration:

n = 0.03015*0.5137 = 0.01549

Which is also the number of moles of the acid. The molar mass is the mass, in g, divided by the number of moles:

M = 2.79/0.01549

M = 180 g/mol

After reacting with the base, the conjugate base of the acid will be formed, and the equilibrium between the acid form (HA) and the conjugate base (A⁻) is a buffer. It formed 0.01549 moles of A⁻, which will react with the moles of H⁺ from HCl to form HA.

nH⁺ = nHCl = 0.01741*0.448 = 0.0078 mol

A⁻ + H⁺ ⇄ HA

0.01549 0.0078 0 Initial

-0.0078 -0.0078 +0.0078 Reacts

0.0078 0 0.0078 Equilibrium

For a buffer, the pH can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[A⁻]/[HA]

Because the volume is the same, we can use the number of moles instead of the concentration:

3.48 = pKa + log(0.0078/0.0078)

pKa = 3.48

pKa = -logKa

Ka = $10^{-pKa}$

Ka = $10^{-3.48}$

Ka = 3.31x10⁻⁴

5 0

3 years ago

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Marta_Voda [28]

Low levels of high blood pressure to insure it

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3 years ago

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Identify the power of ten that defines each of these prefixes. Input your answers as 10 x where x is the power of ten. nano- ___

Gemiola [76]

Answer: The quantity of every prefix is written below as a power of ten.

Explanation:

In the metric system of measurement, the name of multiples and subdivision of any unit is done by combining the name of the unit with the prefixes.

For Example: deka, hecto and kilo means 10, 100 and 1000 respectively. Deci, centi and milli means one-tenth, one-hundredth, and one-thousandth respectively.

The quantity of these prefixes are written as the power of 10.

For the given prefixes:

Nano: The quantity will be $10^{-9}$