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3 years ago

All samples of an element are composed of atoms with the same

2 answers:

6 0

All samples of an element are composed of atoms having the same number of protons. The number of protons determines its place on the periodic table and its atomic number. Therefore the atomic number is the amount of protons an element has contained within its nucleus. Elements can have various isotopes that each have a different mass. The answer is 1. atomic mass.

inysia [295]3 years ago

3 0

Answer is: 2. atomic number.

Atomic number is unique and defines an element. Atomic number (Z) is total number of protons in an atom.

For example, nitrogen atom (N-14) has 7 protons (p⁺), 7 electrons (e⁻) and 7 neutrons (n°). Protons (positive charge) and neutrons are in the nucleus of atom, electrons (negative charge) are bound to the nucleus in spherical shells. Nitrogen is an element with atomic number 7. Mass number (A) is the total number of protons and neutrons in a nucleus. Nitrogen mass number is 14 (A = p⁺ + n°; A = 14).

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What is the boiling point elevation constant, Kb, of diethyl ether if 38.2 g of the nonelectrolyte benzophenone, C6H5COC6H5, dis

kakasveta [241]

Answer: the boiling point elevation constant is $1.73^0C/m$

Explanation:

Elevation in boiling point is given by:

$\Delta T_b=i\times K_b\times m$

$\Delta T_b=T_b-T_b^0=$ = Elevation in boling point

i= vant hoff factor = 1 (for non electrolyte)

$K_b$ =boiling point constant = ?

m= molality

$\Delta T_b=i\times K_b\times \frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}$

Weight of solvent (diethylether)= 330 g = 0.33 kg

Molar mass of solute (benzophenone)= 182 g/mol

Mass of solute (benzophenone) = 38.2 g

$(35.7-34.6)^0C=1\times K_b\times \frac{38.2g}{182g/mol\times 0.33kg}$

$K_b=1.73^0C/m$

Thus the boiling point elevation constant is $1.73^0C/m$

3 0

3 years ago

What is the pH of a 0.0042 M hydrochloric acid solution?

babymother [125]

Answer:

E) 2.38

Explanation:

The pH of any solution , helps to determine the acidic strength of the solution ,

i.e. ,

Lower the value of pH , higher is its acidic strength

and ,

Higher the value of pH , lower is its acidic strength .

pH is given as the negative log of the concentration of H⁺ ions ,

hence ,

pH = - log H⁺

From the question ,

the concentration of the solution is 0.0042 M , and being it a strong acid , dissociates completely to its respective ions ,

Therefore , the concentration of H⁺ = 0.0042 M .

Hence , using the above equation , the value of pH can be calculated as follows -

pH = - log H⁺

pH = - log ( 0.0042 M )

pH = 2.38 .

4 0

3 years ago

What is a liquid mixture whose parts are evenly blended?.

Ilia_Sergeevich [38]

Homogeneous mixture

5 0

2 years ago

Read 2 more answers

If a liquid substance is transferred to a different container, what can be predicted about the volume of the liquid in the new c

taurus [48]

The same

Explanation:

If a liquid substance is transferred to a different container, the volume of the liquid in the new container will remain the same.

The volumes of liquids are fixed and does not change. Wherever they are contained, just like solids, they maintain their constant space.

Volume is the amount of space occupied by a body.
Gases do not have fixed volume as they fill their containers and they take up the shape.
Solids and liquids have a fixed volume.
They do not change their volume.

learn more:

State of matter brainly.com/question/10972073

#learnwithBrainly

8 0

3 years ago

How much heat does it take to melt 5.0g solid copper?

Leya [2.2K]

Answer:

$Q=1.04kJ$

Explanation:

Hello,

In this case, for latent heat (phase change) we need to consider the enthalpy associated with the involved process, here, melting or fusion; thus, the enthalpy of fusion of copper is 13.2 kJ/mol, therefore, the heat is computed as:

$Q=m\Delta H_{fus}$

Nevertheless, since the given enthalpy is per mole of copper, we need to use its atomic mass to perform the correct calculation as follows:

$Q=5.0g*\frac{1mol}{63.54}* 13.2\frac{kJ}{mol}\\ \\Q=1.04kJ$

Which is positive as it needs to be supplied to the system.

Best regards.

5 0

3 years ago