What is an atomic nucleus?

s2008m [1.1K]

Answer:

Nuclear properties

Naturally occurring beryllium, save for slight contamination by the cosmogenic radioisotopes, is isotopically pure beryllium-9, which has a nuclear spin of 3/2.Beryllium is alloyed with copper or nickel to make springs, gyroscopes, electrical contacts, spot-welding electrodes and non-sparking tools, according to the Royal Society of Chemistry. Other beryllium alloys are used in high-speed aircrafts and missiles, as well as spacecraft and communication satellites.

Explanation:

hope this helps if not let me know

5 0

2 years ago

Lead(II) sulfide, PbS, reacts with oxygen gas to produce lead(II)oxide and dioxide. If 0.500 moles of O2 were consumed using thi

Andreas93 [3]

I think you mean:
".. reacts with oxygen gas to produce lead (II) oxide and 'sulfur' dioxide..."

The balanced chemical reaction would be
2PbS + 3O2 --> 2PbO + 2SO2

The stiochiometric ratio is this: 3 moles of O2 produces 2 moles of lead (II) oxide. So,

0.500 moles (2/3) = 0.333 moles

Therefore, 0.333 moles of PbO is produced when 0.500 moles of O2 reacts with PbS.

5 0

3 years ago

153 mL of 2.5 M HF is reacted with an excess of Ca(OH)2. How many grams of CaF2 will be produced?

Delvig [45]

Answer:

15 g

Explanation:

Data given:

amount of HF = 153 mL 2.5 M HF

amount of Ca(OH)₂ = Excess

grams of CaF₂ = ?

Reaction Given:

2HF + Ca(OH)₂ ------→ 2H₂O + CaF₂

Solution:

First we have to find number of moles of HF in 153 mL of 2.5 M HF

For this we will use following formula

Molarity = moles of solute / liter of solution

Rearrange above equation

moles of solute = Molarity x liter of solution . . . . . (1)

Put values in above equation (1)

moles of solute = 2.5 x 1 L

moles of solute = 2.5

So,

we come to know that there are 2.5 moles of solute (HF) in 1 L of solution

Now how many moles of solute will be present in 153 ml of solution

Convert 153 mL to Liter

1000 mL = 1 L

153 mL = 153/1000 = 0.153 L

Apply Unity Formula

2.5 moles HF ≅ 1 L solution

X moles of HF ≅ 0.153 L solution

moles of HF = 2.5 moles x 0.153 mL solution / 1 L solution

moles of HF = 0.383 moles

So, 153 mL contains 0.383 moles of HF

Now Look at the reaction:

2HF + Ca(OH)₂ ------→ 2H₂O + CaF₂

2 mol 1 mol

From the reaction we come to know that 2 moles of HF gives 1 mole of CaF₂ then how many moles of CaF₂ will be produced from o.383 moles of HF

Apply Unity Formula

2 moles HF ≅ 1 mole of CaF₂

0.383 moles of HF ≅ X moles of CaF₂

moles of CaF₂ = 0.383 moles x 1 mole / 2 mol

moles of CaF₂ = 0.192 moles

So, 0.192 moles of CaF₂ will be produced by 0.383 moles of HF

Now we will find mass of 0.192 moles of CaF₂

Formula will be used

mass in grams = no. of moles x molar mass . . . . . . . (2)

molar mass of CaF₂ = 40 + 2(19)

molar mass of CaF₂ = 40 + 38 = 78 g/mol

Put values in eq. 2

mass in grams = 0.192 x 78 g/mol

mass in grams = 14.976 g

rounding the value

mass in grams = 15 g

So,153 mL of 2.5 M HF is reacted with an excess of Ca(OH)₂ will produce 15 g of CaF₂.

6 0

4 years ago

In which of the following compounds does the carbonyl stretch in the IR spectrum occur at the lowest wavenumber?

klio [65]

Answer:

a. Cyclohexanone

Explanation:

The principle of IR technique is based on the vibration of the bonds by using the energy that is in this region of the electromagnetic spectrum. For each bond, there is a specific energy that generates a specific vibration. In this case, you want to study the vibration that is given in the carbonyl group C=O. Which is located around 1700 cm-1.

Now, we must remember that the lower the wavenumber we will have less energy. So, what we should look for in these molecules, is a carbonyl group in which less energy is needed to vibrate since we look for the molecule with a smaller wavenumber.

If we look at the structure of all the molecules we will find that in the last three we have heteroatoms (atoms different to carbon I hydrogen) on the right side of the carbonyl group. These atoms allow the production of resonance structures which makes the molecule more stable. If the molecule is more stable we will need more energy to make it vibrate and therefore greater wavenumbers.

The molecule that fulfills this condition is the cyclohexanone.

See figure 1

I hope it helps!

4 0

4 years ago

The strongest intermolecular interactions between propanol (CH3CH2CH2OH) molecules arise from hydrogen bonding

pickupchik [31]

The claim that the strongest intermolecular interactions between propanol molecules arises from hydrogen bonding is True.

Intermolecular forces are weaker attraction forces that are utilized to define physical characteristics of molecules such as:

boiling point
temperature
density
melting points

Hydrogen bonding is an type of intermolecular forces.

It is a type of dipole-dipole interaction that only happens when a hydrogen atom is connected to the atomic element of oxygen, nitrogen, or fluorine.

From the question given, in the propanol (CH3CH2CH2OH) molecule, the hydrogen usually has a partially positive charge which attracts the partially negative charge of the oxygen.

Therefore, we can conclude that the claim is True.

Learn more about Hydrogen Bonding here:

brainly.com/question/10904296?referrer=searchResults

3 0

3 years ago