Uranium-238 (U-238) decays into lead-206 (Pb-206). Which of the following is a true statement?

The “fatal flaw” in Rutherford’s model of the atom was the idea that if the electrons were ________.

Wittaler [7]

The correct option is A. Rutherford model of the atom consider an atom to be made up of a central nucleus with electrons orbiting around it. The nucleus is considered to be tiny, heavy and its positively charged while the electrons are negatively charged. The shortcoming of this model is that it was not able to explain how the positive nucleus was not able to attract the negative electrons and pull them inside the nucleus.

8 0

3 years ago

True or false organic protein catalysts are precipitates

Dmitry_Shevchenko [17]

The answer is true lol

7 0

3 years ago

Element A has an electronegativity of 0.8 and element B has an electronegativity of 3.0. Which statement best describes the bond

Advocard [28]

Answer:

C) The compound is largely ionic with A as the cation.

Explanation:

Pulings proposed the method to determine if the compound is ionic in nature or covalent in nature , by finding the difference between the electronegativity of the respective cation and anion .

The ion with higher electronegativity is the anion and the ion with lower electronegativity is the cation.

The electronegativity difference above 1.7 make the compound ionic in nature.

Hence, from the question ,

A is the cation and B is the anion.

And the electronegativity difference above 1.7 so the compound is ionic in nature.

8 0

3 years ago

Carlos is making phosphorus trichloride using the equation below.

hjlf

Answer:

C.) 2

Explanation:

Chemical equations, in a way, can be seen as algebraic equations. Cl2 is a molecular structure, so, there are two Cl atoms. 3Cl2 means 3, Cl2 molecules. So, if we think of it as adding up all the atoms, we will get, 2 P atoms and 6 Cl atoms. Now to convert. The Law of the Conservation of Mass basically says you can't add or subtract atoms out of nowhere, so the number of atoms has to stay the same when it's being converted. We need to place a coefficient with PCl3. If we look at PCl3, it shows us that there are three Cl atoms and one P atom. And looking back at how many atoms there were on the left side of the equation, we just need to double the atoms of atoms so it will be equal. So, the answer is C.) 2

BRAINLIEST PLEASE!!

7 0

2 years ago

Calculate the pH for each of the cases in the titration of 25.0 mL of 0.180 M pyridine, C 5 H 5 N ( aq ) with 0.180 M HBr ( aq )

Oxana [17]

Answer:

Explanations

Calculate the pH for each of the following cases in thetitration of 25.0 mL of 0.100 M pyridine, C5H5N(aq) with 0.100 MHBr(aq):

a.Before and addition of HBr

b.After addition of 12.5ml HBr

c.After addition of 15ml HBr

d.After addition of 25ml HBr

e.After addition of 33ml HBr

SOLUTION ;;;

Kb of pyridine =1.5*10^-9

a)let the dissociation be x.so,

kb=x^2/(0.1-x)

or 1.5*10^-9=x^2/(0.1-x)

or x=1.225*10^-5

so,

[OH-]=1.225*10^-5

so,

pOH=-log([OH-])

so pH=9.088

b)now this will effectively behave as a buffer

pKb=8.82

so pOH=pKb+log(salt/acid)

=8.82+log((12.5*0.1)/(25*0.1-12.5*0.1))

=8.82

so pH=14-pOH

=5.18

c)again using the same equation as the above,

pOH=pKb+log(salt/acid)

=8.82+log((15*0.1)/(25*0.1-15*0.1))

=9

so pH=14-9

=5

d)now the base is completely neutralised.so,

concentration of the salt formed=0.1/2

=0.05 M

so,

pH=7-0.5pKb-0.5log(C)

=7-0.5*8.82-0.5*log(0.05)

=3.24

e)concentration of H+=(33*0.1-25*0.1)/(33+25)

=0.01379

so pH=-log(0.01379)

=1.86

4 0

3 years ago

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