All of the following pairs of ions are isoelectronic except which one?

How can you find the number of neutrons that are in an atom of an element

Temka [501]

Answer:

You just have to take the periodic table of the elements, take the element that interests you. Then, you look at the formula of the element, at the top left you find the number of neutrons and protons and at the bottom left you find the number of protons. Then you just have to make the number from the top left minus the number from the bottom left.

Explanation:

4 0

3 years ago

It takes 945. kJ/mol to break a nitrogen-nitrogen triple bond. Calculate the maximum wavelength of light for which a nitrogen-ni

kolezko [41]

Answer: 1.274 * 10^ -7 meter (same as 127.4 nanometers

Explanation:

It's given that the energy

required to break the N N triple bond is 945 * 10^3 joules per mole.

One mole contains 6.02 * 10^ 23 molecules, so the energy required per molecule

= 945 * 10^3 / 6.023 * 10^23, or 1.56 * 10^-18 joules.

Then we need a photon whose energy (E) is at least that amount.

The energy E of a photon is related to its frequency f by PLANCK'S EQUATUON,

E = hf,

where h is Planck's constant (6.625 * 10^-34 joule-sec)

and the wavelength w is inversely proportional to the frequency by w = c/f, where c is the speed of light, 2.998 * 10^8 meters per sec.

If h & c are both constants, their product hc is constant, so we can say E = hc/w,

or if we know E and want to find w, a little algebra gives: w = hc/E.

The product hc = 1.9875 * 10^-25 joule-meters,

so w = 1.9875 * 10^-25 / 1.56 * 10^-18, or 1.274 * 10^ -7 meter (same as 127.4 nanometers

6 0

3 years ago

Which models are most appropriate for him to use?

jekas [21]

Answer:

the triangular model and the cubic model

5 0

3 years ago

Read 2 more answers

A rigid tank contains 0.66 mol of oxygen (O2). Find the mass of oxygen that must be withdrawn from the tank to lower the pressur

dsp73

Answer:

12.8 g of $O_{2}$ must be withdrawn from tank

Explanation:

Let's assume $O_{2}$ gas inside tank behaves ideally.

According to ideal gas equation- $PV=nRT$

where P is pressure of $O_{2}$ , V is volume of $O_{2}$ , n is number of moles of $O_{2}$ , R is gas constant and T is temperature in kelvin scale.

We can also write, $\frac{V}{RT}=\frac{n}{P}$

Here V, T and R are constants.

So, $\frac{n}{P}$ ratio will also be constant before and after removal of $O_{2}$ from tank

Hence, $\frac{n_{before}}{P_{before}}=\frac{n_{after}}{P_{after}}$

Here, $\frac{n_{before}}{P_{before}}=\frac{0.66mol}{43atm}$ and $P_{after}=17atm$

So, $n_{after}=\frac{n_{before}}{P_{before}}\times P_{after}=\frac{0.66mol}{43atm}\times 17atm=0.26mol$

So, moles of $O_{2}$ must be withdrawn = (0.66 - 0.26) mol = 0.40 mol

Molar mass of $O_{2}$ = 32 g/mol

So, mass of $O_{2}$ must be withdrawn = $(32\times 0.40)g=12.8g$

7 0

3 years ago

Question 7

astraxan [27]

Answer:

tama yon sagot nya gayahin mo nalang

8 0

3 years ago