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2 years ago

Will give brainliest

Chemistry

1 answer:

mote1985 [20]2 years ago

7 0

Answer:

1)Around 450 B.C., the Greek philosopher Democritus introduced the idea of the atom.

2)All matter is made of atoms, Atoms are indivisible and indestructible.Compounds are formed by a combination of two or more different kinds of atoms, A chemical reaction is a rearrangement of atoms.

3)B

Explanation:

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Use MO diagrams to place B2+, B2, and B2- in order of (a) decreasing bond energy; (b) decreasing bond length.

shepuryov [24]

We use the MO diagram for a homonuclear diatomic species (since C and N are neighbours, we treat them as the "same").

The first two electrons contribute to bonding. The next two are anti-bonding.

The next six contribute to bonding, and the following six are anti-bonding.

So, if we start with CN+, which has 4+5-1 (8) valence electrons, we note that the first two electrons contribute to bonding, while the next two cancel this out; the next four contribute to bonding, so the bond order is 4/2 = 2.

If we add one more electron to get CN, there are now 5 bonding electrons, giving bond order 5/2=2.5.

Adding one more to give CN- would give the bond order 6/2 = 3. (If we added more electrons, each one would lower the bond order.)

Given a series of molecules with identical skeletal structures, the one with the highest bond order has the highest bond energy:

CN+ < CN < CN-

Lewis structures will verify that CN- has a triple bond, but they do not work particularly well for CN+ and CN.

learn more about bond orders at

brainly.com/question/9713842

#SPJ1

3 0

1 year ago

An air bubble with a volume of 5.0 ml is released at the bottom of a lake where the pressure is 3.0 atm. when it reaches the sur

Svetradugi [14.3K]

The new volume of the air bubble that has an initial volume of 5.0 ml released at the bottom of a lake where the pressure is 3.0 atm is 15mL.

<h3>How to calculate volume?</h3>

The volume of a given gas can be calculated by using the following formula:

P1V1 = P2V2

Where;

P1 = initial pressure
V1 = initial volume
P2 = final pressure
V2 = final volume

5 × 3 = 1 × V2

15 = V2

V2 = 15mL

Therefore, the new volume of the air bubble that has an initial volume of 5.0 ml released at the bottom of a lake where the pressure is 3.0 atm is 15mL.

Learn more about volume at: brainly.com/question/1578538

7 0

2 years ago

PLEASE HELPPPP!!!!!

Likurg_2 [28]

Answer : The mass of nitric acid is, 214.234 grams.

Solution : Given,

Moles of nitric acid = 3.4 moles

Molar mass of nitric acid = 63.01 g/mole

Formula used :

$\text{Mass of }HNO_3=\text{Moles of }HNO_3\times \text{Molar mass of }HNO_3$

Now put all the given values in this formula, we get the mass of nitric acid.

$\text{Mass of }HNO_3=(3.4moles)\times (63..01g/mole)=214.234g$

Therefore, the mass of nitric acid is, 214.234 grams.

6 0

2 years ago

The atomic masses of 151eu and 153eu are 150.919860 and 152.921243 amu, respectively. The average atomic mass of europium is 151

vitfil [10]

Answer:- The natural abundance of $^1^5^1_E_u$ is 0.478 or 47.8% and $^1^5^3_E_u$ is 0.522 or 52.2% .

Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:

Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)

We have been given with atomic masses for $^1^5^1_E_u$ and $^1^5^3_E_u$ as 150.919860 and 152.921243 amu, respectively. Average atomic mass of Eu is 151.964 amu.

Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of $^1^5^1_E_u$ as n then the abundance of $^1^5^3_E_u$ would be 1-n .

Let's plug in the values in the formula:

$151.964=150.919860(n)+152.921243(1-n)$