The two rate statements below are not the same. Use the concept of unit rates to explain

What is 2n^2 rule ( of science)

lozanna [386]

2n² rule:

This rule is used to determine number of electrons in particular shell.

n=1 means K shell

n=2 means L shell

n=3 means M shell

n=4means N shell

The first K shell can hold upto 2 electrons, L shell can hold up to 8, third M shell can hold up to 18and the fourth N shell can hold upto 32 electrons. This rule of arrangement of electrons according to the shell is known 2n2 rule where n means number of shell.

For example: There is one proton in the nucleus of hydrogen atom, which moves in K shell path. It has no neutron.

3 0

3 years ago

Blood samples for research or medical tests sometimes have heparin added. Why is this done?

alina1380 [7]

It is essential for accurate results that the correct volume of blood is sampled to achieve a correct concentration (and dilution, if liquid heparin is used), and that blood and anticoagulant are well mixed immediately after sampling.

8 0

3 years ago

How many electrons are there in carbonate ion, CO3^-2?

NISA [10]

It should be 24 electrons

3 0

3 years ago

Alveoli are tiny sacs of air in the lungs. Their average diameter is 4.50 × 10−5 m. Calculate the uncertainty in the velocity of

Arisa [49]

<u>Answer:</u> The uncertainty in the velocity of oxygen molecule is $4.424\times 10^{-5}m/s$

<u>Explanation:</u>

The diameter of the molecule will be equal to the uncertainty in position.

The equation representing Heisenberg's uncertainty principle follows:

$\Delta x.\Delta p=\frac{h}{2\pi}$

where,

$\Delta x$ = uncertainty in position = d = $4.50\times 10^{-5}m$

$\Delta p$ = uncertainty in momentum = $m\Delta v$

m = mass of oxygen molecule = $5.30\times 10^{-26}kg$

h = Planck's constant = $6.627\times 10^{-34}kgm^2/s^2$

Putting values in above equation, we get:

$4.50\times 10^{-5}m\times 5.30\times 10^{-26}kg\times \Delta v=\frac{6.627\times 10^{-34}kgm^2/s}{2\times 3.14}\\\\\Delta v=\frac{6.627\times 10^{-34}kgm^2/s^2}{2\times 3.14\times 4.50\times 10^{-5}m\times 5.30\times 10^{-26}kg}=4.424\times 10^{-5}m/s$

Hence, the uncertainty in the velocity of oxygen molecule is $4.424\times 10^{-5}m/s$

8 0

3 years ago

Solid NaBr is slowly added to a solution that is 0.073 M in Cu+ and 0.073 M in Ag+.Which compound will begin to precipitate firs

saul85 [17]

Answer :

AgBr should precipitate first.

The concentration of $Ag^+$ when CuBr just begins to precipitate is, $1.34\times 10^{-6}M$

Percent of $Ag^+$ remains is, 0.0018 %

Explanation :

$K_{sp}$ for CuBr is $4.2\times 10^{-8}$

$K_{sp}$ for AgBr is $7.7\times 10^{-13}$

As we know that these two salts would both dissociate in the same way. So, we can say that as the Ksp value of AgBr has a smaller than CuBr then AgBr should precipitate first.

Now we have to calculate the concentration of bromide ion.

The solubility equilibrium reaction will be:

$CuBr\rightleftharpoons Cu^++Br^-$