Blonde hair is a dominant trait. (True or flase)

What are blocks of time in the geological time scale called?

Katena32 [7]

B is the answer , i got you

7 0

3 years ago

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Identify this compound: KClO4

lidiya [134]

Answer: Potassium perchlorate

Explanation:

3 0

3 years ago

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How does electron repulsion in the outer shell cause anions to be larger than their atoms?

Alexeev081 [22]

The anion is also larger than the atom because of electron-electron repulsion. As more electrons are added to the outer shell, and even to higher principle energy levels, the repulsion bewteen the negatively charged particles grows, pushing the shells farther from the nucleus.

5 0

3 years ago

Use the data given below to construct a Born-Haber cycle to determine the second ionization energy of Ca. Δ H°(kJ) Ca(s)→Ca(g) 1

Drupady [299]

Answer : The value of second ionization energy of Ca is 1010 kJ.

Explanation :

The formation of calcium oxide is,

$Ca(s)+\frac{1}{2}O_2(g)\overset{\Delta H_f}\rightarrow CaO(s)$

$\Delta H_f^o$ = enthalpy of formation of calcium oxide = -635 kJ

The steps involved in the born-Haber cycle for the formation of $CaO$ :

(1) Conversion of solid calcium into gaseous calcium atoms.

$Ca(s)\overset{\Delta H_s}\rightarrow Ca(g)$

$\Delta H_s$ = sublimation energy of calcium = 193 kJ

(2) Conversion of gaseous calcium atoms into gaseous calcium ions.

$Ca(g)\overset{\Delta H_I_1}\rightarrow Ca^{+1}(g)$

$\Delta H_I_1$ = first ionization energy of calcium = 590 kJ

(3) Conversion of gaseous calcium ion into gaseous calcium ions.

$Ca^{+1}(g)\overset{\Delta H_I_2}\rightarrow Ca^{+2}(g)$

$\Delta H_I_2$ = second ionization energy of calcium = ?

(4) Conversion of molecular gaseous oxygen into gaseous oxygen atoms.

$O_2(g)\overset{\Delta H_D}\rightarrow OI(g)$

$\frac{1}{2}O_2(g)\overset{\Delta H_D}\rightarrow O(g)$

$\Delta H_D$ = dissociation energy of oxygen = $\frac{498}{2}=249kJ$

(5) Conversion of gaseous oxygen atoms into gaseous oxygen ions.

$O(g)\overset{\Delta H_E_1}\rightarrow O^-(g)$

$\Delta H_E_1$ = first electron affinity energy of oxygen = -141 kJ

(6) Conversion of gaseous oxygen ion into gaseous oxygen ions.

$O^-(g)\overset{\Delta H_E_2}\rightarrow O^{2-}(g)$

$\Delta H_E_2$ = second electron affinity energy of oxygen = 878 kJ

(7) Conversion of gaseous cations and gaseous anion into solid calcium oxide.

$Ca^{2+}(g)+O^{2-}(g)\overset{\Delta H_L}\rightarrow CaO(s)$

$\Delta H_L$ = lattice energy of calcium oxide = -3414 kJ

To calculate the overall energy from the born-Haber cycle, the equation used will be:

$\Delta H_f^o=\Delta H_s+\Delta H_I_1+\Delta H_I_2+\Delta H_D+\Delta H_E_1+\Delta H_E_2+\Delta H_L$

Now put all the given values in this equation, we get:

$-635kJ=193kJ+590kJ+\Delta H_I_2+249kJ+(-141kJ)+878kJ+(-3414kJ)$

$\Delta H_I_2=1010kJ$

Therefore, the value of second ionization energy of Ca is 1010 kJ.

6 0

3 years ago

As the distance between 2 objects increases, what happens to gravitational force?

cestrela7 [59]

Answer:

Gravitational force decreases

Explanation:

One of Newton's remarkable discoveries was the law of universal gravitation, according to which if two bodies have mass, when they are close to each other there is a force of attraction between them. Thus, for example, the Earth attracts the Moon and the Sun to the Earth. For our purposes, the important thing about this law is that it tells us, first of all, that the force between the bodies depends on the distance between them. It does not matter to have two bodies very close to each other that are very separate. The greater the distance between the bodies, the smaller the force between them, since as the distance between two bodies is greater, the smaller the effect that one exerts on the other.

Second, the law of universal gravitation tells us how the force of distance depends. Suppose two bodies are at a distance of one meter and the force has a certain value. If the distance between these same bodies increases twice, that is to 2 m, then the force decreases to a quarter. If the distance increases to triple, that is to 3 m, the force decreases to the ninth part, and so on.

The fourth part of the force is equal to 1/4; but 4 = 2², that is, 2 raised to power 2; So the fourth part is equal to 1/2.

The ninth part of the force is equal to 1/9; but 9 = 3², that is, 3 raised to power 2; So the ninth part is equal to 1 / 3², etc. Consequently: if the distance increases 2 times, the force decreases 1/2 times; if the distance increases 3 times, the force decreases 1 / 3² times; if the distance increases 4 times, the force decreases 1/4 times, and so on.

The latter is expressed by saying that the decrease in the value of the force is like the square of the distance. In abbreviated form, using mathematical language the above is expressed by saying that force depends inversely proportional to the square of distance. Conversely it means that increasing distance decreases force

4 0

4 years ago

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Blonde hair is a dominant trait. (True or flase)​

Blonde hair is a dominant trait. (True or flase)