An isotope of manganese has 25 protons and 30 neutrons. What is the mass number of this isotope?

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Stels [109]

Answer:

C....................

5 0

3 years ago

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A) Compute the repeat unit molecular weight of polystyrene. B) Compute the number-average molecular weight for a polystyrene for

Andrej [43]

Answer:

Explanation:

In Polystrene, the molecular formula for the repeat unit = $C_8H_8$ ;

and the atomic weights of Carbon C = 12.01 g/mol

For Hydrogen, it is 1.01 g/mol

Hence, the repeat unit molecular weight is:

m = 8 (12.01 g/mol)+8(1.01 g/mol)

m = 96.08 g/mol + 8.08 g/mol

m = 104.16 g/mol

The degree of polymerization = no-average molecular weight/repeat unit molecular weight.

Mathematically;

$DP = \dfrac{\overline M_n}{m}$

$\overline M_n= DP \times m$

$\overline M_n= 25000 \times 104.16 \ g/mol$

$\overline M_n= 2604000 \ g/mol$

7 0

3 years ago

Which sample contains the largest number of oxygen atoms? Select one: a. 8.0 g of carbon dioxide b. 8.0 g of potassium chlorate

adell [148]

The sample with the largest number of oxygen atoms will be calcium perchlorate.

<h3>Number of atoms in a compound</h3>

Since we are not looking at the number of moles, the mass of the compounds has no bearing on the number of atoms of oxygen.

The chemical formula for carbon dioxide is $CO_2$ . Thus, it has 2 atoms of oxygen.
The chemical formula for potassium chlorate is $KClO_3$ . Thus, it has 3 oxygen atoms.
The chemical formula for calcium perchlorate is $Ca(ClO_4)_2$ . Thus, it has 8 atoms of oxygen.
The chemical formula for sodium hydroxide is NaOH. Thus, it has 1 atom of oxygen.

Therefore, the compound with the largest number of oxygen atoms is calcium perchlorate.

More on the number of atoms in compounds can be found here: brainly.com/question/1686912

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5 0

2 years ago

according to the third law if a football player hits another player with an action force of 1500n how much will the reaction for

djyliett [7]

Answer:

The reaction would be 1500n (equal reaction)

Explanation:

This can be explained by Newton's third law of motion which states that for every action (force), there is an opposite and equal reaction. In other words, when two objects or people come in contact, the magnitude of force which they exert on each other is equal and they both feel an equal reaction force.

It doesn't matter whether one of the colliding bodies is of bigger mass than the other. This Newton's third law of motion is also known as the law of action and reaction.

3 0

3 years ago

What is oxidized in a galvanic cell with aluminum and gold electrodes ?

k0ka [10]

Answer:

Aluminum metal

Explanation:

In order to properly answer this or a similar question, we need to know some basic rules about galvanic cells and standard reduction potentials.

First of all, your strategy would be to find a trusted source or the table of standard reduction potentials. You would then need to find the half-equations for aluminum and gold reduction:

$Al^{3+}+3e^-\rightarrow Al; E^o=-1.66 V$

$Au^{3+}+3e^-\rightarrow Au; E^o=1.50 V$

Since we have a galvanic cell, the overall reaction is spontaneous. A spontaneous reaction indicates that the overall cell potential should be positive.

Since one half-equation should be an oxidation reaction (oxidation is loss of electrons) and one should be a reduction reaction (reduction is gain of electrons), one of these should be reversed.

Thinking simply, if the overall cell potential would be obtained by adding the two potentials, in order to acquite a positive number in the sum of potentials, we may only reverse the half-equation of aluminum (this would change the sign of E to positive): $Al\rightarrow Al^{3+}+3e^-; E^o=1.66 V\\Au^{3+}+3e^-\rightarrow Au; E^o=1.50 V$

Notice that the overall cell potential upon summing is:

$E_{cell}=1.66 V + 1.50 V=3.16 V$

Meaning we obey the law of galvanic cells.

Since oxidation is loss of electrons, notice that the loss of electrons takes place in the half-equation of aluminum: solid aluminum electrode loses 3 electrons to become aluminum cation.

6 0

3 years ago