What scientist first developed an equation to calculate the wavelengths of lines in the emission spectrum of hydrogen atoms?.

How many protons neutrons and electrons does nitrogen 14 have?

vazorg [7]

Many nitrogen atoms have seven neutrons<span> (14-7 = 7). Some atoms of nitrogen, however, have eight electrons. They are atoms of N-15, an isotope of nitrogen. In a neutral atom, the number of protons must equal the number of electrons.</span>

5 0

3 years ago

In a high-mass star, hydrogen fusion occurs via the choose one: a. spin-spin interaction. b. proton-proton chain. c. cno cycle.

Lerok [7]

In a high-mass star, hydrogen fusion occurs via the CNO (Carbon-Nitrogen-Oxygen) cycle.

According to the life cycle of a star, there are three main phases in the life of a star: The initial phase (a quick phase), short phase or supergiant phase and death phase or supernova explosion.

the CNO cycle means Carbon-Nitrogen-Oxygen cycle and this process tale place during main sequence phase.

In this phase, hydrogen fuses into helium as a result of six different reaction taking place inside a star.

The first step of the sequence begins when the nucleus of carbon 12 isotope emits gamma rays after capturing a proton and produces nitrogen-13.

This whole cycle is known as stellar nucleosynthesis.

If you need to learn more about Carbon-Nitrogen Cycle click here:

brainly.com/question/13022835

#SPJ4

8 0

2 years ago

The standard free energy change for a reaction in an electrolytic cell is always:_________

sattari [20]

Answer: The standard free energy change for a reaction in an electrolytic cell is always positive.

Explanation:

Electrolytic cells use electric currents to drive a non-spontaneous reaction forward.

Relation of standard free energy change and emf of cell

$\Delta G^o=-nFE^0_{cell}$

where,

$\Delta G^o$ = standard free energy change

n= no of electrons gained or lost

F= faraday's constant

$E^0_{cell}$ = standard emf

$E^0_{cell}$ = standard emf = -ve , for non spontaneous reaction

Thus $\Delta G^o=(-ve)(-ve)=+ve$

Thus standard free energy change for a reaction in an electrolytic cell is always positive.

8 0

3 years ago

Explain why the place of aluminum in the reactivity wagon seems to be unsuitable.

Step2247 [10]

Answer:

Acids react with most metals.

When an acid reacts with a metal, the products are a salt and hydrogen.

This is the general word equation for the reaction: metal + acid → salt + hydrogen

Explanation:

5 0

2 years ago

Calculate the enthalpy of the reaction

harkovskaia [24]

Answer : The enthalpy of the reaction is, -2552 kJ/mole

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The given enthalpy of reaction is,

$4B(s)+3O_2(g)\rightarrow 2B_2O_3(s)$ $\Delta H=?$

The intermediate balanced chemical reactions are:

(1) $B_2O_3(s)+3H_2O(g)\rightarrow 3O_2(g)+B_2H_6(g)$ $\Delta H_A=+2035kJ$

(2) $2B(s)+3H_2(g)\rightarrow B_2H_6(g)$ $\Delta H_B=+36kJ$

(3) $H_2(g)+\frac{1}{2}O_2(g)\rightarrow H_2O(l)$ $\Delta H_C=-285kJ$

(4) $H_2O(l)\rightarrow H_2O(g)$ $\Delta H_D=+44kJ$

Now we have to revere the reactions 1 and multiple by 2, revere the reactions 3, 4 and multiple by 2 and multiply the reaction 2 by 2 and then adding all the equations, we get :

(when we are reversing the reaction then the sign of the enthalpy change will be change.)

The expression for enthalpy of the reaction will be,

$\Delta H=-2\times \Delta H_A+2\times \Delta H_B-6\times \Delta H_C-6\times \Delta H_D$

$\Delta H=-2(+2035kJ)+2(+36kJ)-6(-285kJ)-6(+44)$

$\Delta H=-2552kJ$

Therefore, the enthalpy of the reaction is, -2552 kJ/mole

4 0

3 years ago