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3 years ago

Question 18 of 25

Chemistry

1 answer:

horsena [70]3 years ago

5 0

Answer:

Explanation:

If the atom is neutral, the sum of the core and valence electrons is the same as the number of protons, which is the atomic number of the element. So if the sum of the core and valence electrons in a neutral atom equals 25 , that is the number of protons in the atomic nucleus, and the atomic number of the element.

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Which method of galaxy formation is expected to dominate far in the future? (1 point

nevsk [136]

Answer:

Dark Matter

Explanation:

90 percent of the mass in the universe is dark matter

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3 years ago

If the mass of a material is 76 grams and the volume of the material is 16 cm3, what would the density of the material be? g/cm3

mafiozo [28]

4.8 g/cm3 with sig figs since it's mass/volume you divide 76 grams by 16 cm3

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3 years ago

Consider the following reaction at constant pressure. Use the information provided below to determine the value of ΔS at 473 K.

Elis [28]

Answer:

The reaction will be spontaneous

Explanation:

To determine if the reaction will be spontaneous or not at this temperature, we need to calculate the Gibbs's energy using the following formula:

$\Delta G= \Delta H - T * \Delta S$

<u>If the Gibbs's energy is negative, the reaction will be spontaneous, but if it's positive it will not.</u>

Calculating the $\Delta G= -1267 - 473 K* \Delta S$ :

$\Delta G= -1267 - 473 K* \Delta S$

Now, other factor we need to determine is the sign of the S variation. When talking about gases, the more moles you have in your system the more enthropic it is.

In this reaction you go from 7 moles to 8 moles of gas, so you can say that you are going from one enthropy to another higher than the first one. This results in: $\Delta S>0[/tex}Back to this expression: [tex]\Delta G= -1267 - 473 K* \Delta S$

If the variation of S is positive, the Gibbs's energy will be negative always and the reaction will be spontaneous.

4 0

4 years ago

What would indicate that a physical change takes place when cooper is drawn into wire

amid [387]

Answer:

When a copper is drawn into wire the only change that occurs is change in its shape and size no change will take place into its composition that is the wires are still possessing the properties of copper metal. Thus, a physical change takes place when copper is drawn into wire.

4 0

3 years ago

Answer these questions based on 234. 04360 as the atomic mass of thorium-234. The masses for the subatomic particles are given.

nikdorinn [45]

The mass defect for the isotope thorium-234 if given mass is 234.04360 amu is 1.85864 amu.

<h3>How do we calculate atomic mass?</h3>

Atomic mass (A) of any atom will be calculated as:

A = mass of protons + mass of neutrons

In the Thorium-234:

Number of protons = 90

Number of neutrons = 144

Mass of one proton = 1.00728 amu

Mass of one neutron = 1.00866 amu

Mass of thorium-234 = 90(1.00728) + 144(1.00866)

Mass of thorium-234 = 90.6552 + 145.24704 = 235.90224 amu

Given mass of thorium-234 = 234.04360 amu

Mass defect = 235.90224 - 234.04360 = 1.85864 amu

Hence required value is 1.85864 amu.

To know more about Atomic mass (A), visit the below link:

brainly.com/question/801533

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2 years ago